EAM potential (LAMMPS cubic hermite tabulation) for hcp and fcc Cobalt developed by Purja Pun and Mishin (2012) v005

Yuri Mishin; Ganga P. Purja Pun

doi:10.25950/8d5b6ade

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EAM_Dynamo_PunMishin_2012_Co__MO_885079680379_005

There is a newer version of this item. See EAM_Dynamo_PunMishin_2012_Co__MO_885079680379_006

Interatomic potential for Cobalt (Co).
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Title A single sentence description.	EAM potential (LAMMPS cubic hermite tabulation) for hcp and fcc Cobalt developed by Purja Pun and Mishin (2012) v005
Description A short description of the Model describing its key features including for example: type of model (pair potential, 3-body potential, EAM, etc.), modeled species (Ac, Ag, ..., Zr), intended purpose, origin, and so on.	We report on the development of an embedded-atom interatomic potential representing basic properties of both the hcp and the fcc phases of cobalt with nearly equal accuracy. The potential also reproduces the structural phase transformation between the two phases at a temperature close to the experimental value. The proposed potential can be used for large-scale atomistic simulations of cobalt microstructures over a wide range of temperatures. In a more general context, it offers a model for studying thermodynamic and kinetic properties of hcp/fcc interfaces and microstructure evolution in two-phase materials.
Species The supported atomic species.	Co
Disclaimer A statement of applicability provided by the contributor, informing users of the intended use of this KIM Item.	The potential accurately represents most of the properties of the hcp and the fcc phases of Co including the phase transition temperature.
Content Origin	http://www.ctcms.nist.gov/potentials/Co.html

Contributor	Ganga P. Purja Pun
Maintainer	Ganga P. Purja Pun
Developer	Yuri Mishin Ganga P. Purja Pun
Published on KIM	2018
How to Cite	Click here to download this citation in BibTeX format.
Citations This panel presents information regarding the papers that have cited the interatomic potential (IP) whose page you are on. The OpenKIM machine learning based Deep Citation framework is used to determine whether the citing article actually used the IP in computations (denoted by "USED") or only provides it as a background citation (denoted by "NOT USED"). For more details on Deep Citation and how to work with this panel, click the documentation link at the top of the panel. The word cloud to the right is generated from the abstracts of IP principle source(s) (given below in "How to Cite") and the citing articles that were determined to have used the IP in order to provide users with a quick sense of the types of physical phenomena to which this IP is applied. The bar chart shows the number of articles that cited the IP per year. Each bar is divided into green (articles that USED the IP) and blue (articles that did NOT USE the IP). 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See the Deep Citation documentation for more information. 59 Citations (33 used) Show Model Used Show All Help us to determine which of the papers that cite this potential actually used it to perform calculations. If you know, click the . I. Bryukhanov, V. Gorodtsov, and D. Lisovenko, “Modeling of the Mechanical Properties of Chiral Metallic Nanotubes,” Physical Mesomechanics. 2020. link Times cited: 9 A. A. Deshmukh and S. Pal, “Dynamic probing of structural evolution for Co50Ni50 metallic glass during pressurized cooling using atomistic simulation,” Journal of Molecular Modeling. 2020. link Times cited: 1 H. Sun, Z. Jian, J. Xu, B. Jiang, and C. Liu, “Rapid solidification of cobalt melt by molecular dynamics simulation,” Journal of Thermal Analysis and Calorimetry. 2019. link Times cited: 2 X. Liu, X. Wen, and R. Hoffmann, “Surface Activation of Transition Metal Nanoparticles for Heterogeneous Catalysis: What We Can Learn from Molecular Dynamics,” ACS Catalysis. 2018. link Times cited: 43 Abstract: Many heterogeneous reactions catalyzed by nanoparticles occu… read more Abstract: Many heterogeneous reactions catalyzed by nanoparticles occur at relatively high temperatures, which may modulate the surface morphology of nanoparticles during reaction. Inspired by the discovery of dynamic formation of active sites on gold nanoparticles, we explore theoretically the nature of the highly mobile atoms on the surface of nanoparticles of various sizes for 11 transition metals. Using molecular dynamics simulations, on a 3 nm Fe nanoparticle as an example, the effect of surface premelting and overall melting on the structure and physical properties of the nanoparticles is analyzed. When the nanoparticle is heated up, the atoms in the outer shell appear amorphous already at 900 K. Surface premelting is reached at 1050 K, with more than three liquid atoms, based on the Lindemann criterion. The activated atoms may transfer their extra kinetic energy to the rest of the nanoparticle and activate other atoms. The dynamic studies indicate that the number of highly mobile atoms on the surface increas... read less J. Tranchida, S. Plimpton, P. Thibaudeau, and A. Thompson, “Massively parallel symplectic algorithm for coupled magnetic spin dynamics and molecular dynamics,” J. Comput. Phys. 2018. link Times cited: 76 A. Jokisaari, S. Naghavi, C. Wolverton, P. Voorhees, and O. Heinonen, “Predicting the morphologies of γ’ precipitates in cobalt-based superalloys,” arXiv: Materials Science. 2017. link Times cited: 61 C. Wang, C. Li, J. Han, L. Yan, B. Deng, and X. Liu, “The pressure-temperature phase diagram of pure Co based on first-principles calculations.,” Physical chemistry chemical physics : PCCP. 2017. link Times cited: 2 Abstract: We optimized the high pressure-temperature phase diagram of … read more Abstract: We optimized the high pressure-temperature phase diagram of pure Co up to the liquidus temperature and 120 GPa, based on thermodynamic properties calculated using first-principles. The Gibbs energy for each phase was evaluated in the framework of a quasiharmonic approximation, with a consideration of the thermal electronic contribution at finite temperatures. Particularly, the liquidus temperature, as a function of pressure, was determined using classical Molecular Dynamics simulations. Our results in this work successfully integrated experimental observations and the previous theoretical predictions. The critical solid phase transitions of ε → γf and ε → β were clarified using the Gibbs energy as a function of pressure and temperature. In addition, the magnetism of β above 70 GPa was verified to be nonmagnetic. The difference between γp and β, which was unclear before, has been illustrated to be associated with the magnetic transformation from the paramagnetic state of the γp phase to the nonmagnetic state of the β phase rather than the structural transformation. read less L. Béland, Y. Osetsky, and R. Stoller, “Atomistic material behavior at extreme pressures.” 2016. link Times cited: 26 G. Samolyuk, L. Béland, G. M. Stocks, and R. Stoller, “Electron–phonon coupling in Ni-based binary alloys with application to displacement cascade modeling,” Journal of Physics: Condensed Matter. 2016. link Times cited: 36 Abstract: Energy transfer between lattice atoms and electrons is an im… read more Abstract: Energy transfer between lattice atoms and electrons is an important channel of energy dissipation during displacement cascade evolution in irradiated materials. On the assumption of small atomic displacements, the intensity of this transfer is controlled by the strength of electron–phonon (el–ph) coupling. The el–ph coupling in concentrated Ni-based alloys was calculated using electronic structure results obtained within the coherent potential approximation. It was found that Ni0.5Fe0.5, Ni0.5Co0.5 and Ni0.5Pd0.5 are ordered ferromagnetically, whereas Ni0.5Cr0.5 is nonmagnetic. Since the magnetism in these alloys has a Stoner-type origin, the magnetic ordering is accompanied by a decrease of electronic density of states at the Fermi level, which in turn reduces the el–ph coupling. Thus, the el–ph coupling values for all alloys are approximately 50% smaller in the magnetic state than for the same alloy in a nonmagnetic state. As the temperature increases, the calculated coupling initially increases. After passing the Curie temperature, the coupling decreases. The rate of decrease is controlled by the shape of the density of states above the Fermi level. Introducing a two-temperature model based on these parameters in 10 keV molecular dynamics cascade simulation increases defect production by 10–20% in the alloys under consideration. read less S. Das, B. Javvaji, S. Veerla, and D. R. Mahapatra, “Magnetic nanoparticles for thermal lysis and application in cancer treatment,” SPIE BiOS. 2016. link Times cited: 0 Abstract: Chemotherapy and radiation-therapy are conventional treatmen… read more Abstract: Chemotherapy and radiation-therapy are conventional treatment procedure of cancer. Though radiation therapy is very common practice for cancer treatment, it has limitations including incomplete and non specific destruction. Heating characteristics of magnetic nanoparticle (MNP) is modelled using molecular dynamics simulation setup. This model would give an understanding for the treatment of cancer cell through MNP associated radiation-therapy. In this paper, alternating magnetic field driven heat generation of MNP is studied using classical molecular dynamics. Temperature is measured as an ensemble average of velocity of the atoms. Temperature stabilization is achieved. Under this simulation setting with certain parameters, 45°C temperature was obtained in our simulations. Simulation data would be helpful for experimental analysis to treat cancerous cell in presence of MNP under exposure to radiofrequency. The in vitro thermal characteristics of magnetite nanoparticles using magnetic coil of various frequencies (5, 7.5, 10 and 15 kHz), the saturation temperature was found at 0.5 mg/mL concentration. At frequency 50 kHz the live/dead and MTT assay was performed on magnetite nanoparticles using MC3T3 cells for 10 min duration. Low radio frequency (RF) radiation induced localized heat into the metallic nanoparticles which is clearly understood using the molecular dynamics simulation setup. Heating of nanoparticle trigger the killing of the tumor cells, acts as a local therapy, as it generates less side effects in comparison to other treatments like chemotherapy and radiation therapy. read less S. Risal et al., “Development of the RF-MEAM Interatomic Potential for the Fe-C System to Study the Temperature-Dependent Elastic Properties,” Materials. 2023. link Times cited: 0 Abstract: One of the major impediments to the computational investigat… read more Abstract: One of the major impediments to the computational investigation and design of complex alloys such as steel is the lack of effective and versatile interatomic potentials to perform large-scale calculations. In this study, we developed an RF-MEAM potential for the iron-carbon (Fe-C) system to predict the elastic properties at elevated temperatures. Several potentials were produced by fitting potential parameters to the various datasets containing forces, energies, and stress tensor data generated using density functional theory (DFT) calculations. The potentials were then evaluated using a two-step filter process. In the first step, the optimized RSME error function of the potential fitting code, MEAMfit, was used as the selection criterion. In the second step, molecular dynamics (MD) calculations were employed to calculate ground-state elastic properties of structures present in the training set of the data fitting process. The calculated single crystal and poly-crystalline elastic constants for various Fe-C structures were compared with the DFT and experimental results. The resulting best potential accurately predicted the ground state elastic properties of B1, cementite, and orthorhombic-Fe7C3 (O-Fe7C3), and also calculated the phonon spectra in good agreement with the DFT-calculated ones for cementite and O-Fe7C3. Furthermore, the potential was used to successfully predict the elastic properties of interstitial Fe-C alloys (FeC-0.2% and FeC-0.4%) and O-Fe7C3 at elevated temperatures. The results were in good agreement with the published literature. The successful prediction of elevated temperature properties of structures not included in data fitting validated the potential’s ability to model elevated-temperature elastic properties. read less C.-F. Zhang et al., “NaCl induced active hcp Co nanosheet for hydrogen production and formaldehyde abatement by formaldehyde steam reforming,” Chemical Engineering Journal. 2022. link Times cited: 7 Y.-chao Liang, R. Ma, L.-li Zhou, M. He, Z. Tian, and Y. Mo, “Microstructure Evolution of Ni-Co Alloys During Crystallization and Amorphization Process,” Journal of Superconductivity and Novel Magnetism. 2021. link Times cited: 0 R. Ma et al., “The effect of HCP on the formation of twin boundaries and dislocations in Ni–Co alloys,” Current Applied Physics. 2021. link Times cited: 2 R. Su et al., “High-strength nanocrystalline intermetallics with room temperature deformability enabled by nanometer thick grain boundaries,” Science Advances. 2021. link Times cited: 9 Abstract: Nanometer thick grain boundaries enable room temperature def… read more Abstract: Nanometer thick grain boundaries enable room temperature deformability in conventional brittle intermetallics. Although intermetallics are attractive for their high strength, many of them are often brittle at room temperature, thereby severely limiting their potential as structural materials. Here, we report on a previously unidentified deformable nanocrystalline CoAl intermetallics with Co-rich thick grain boundaries (GBs). In situ micropillar compression studies show that nanocrystalline CoAl with thick GBs exhibits ultrahigh yield strength, exceeding 4.5 gigapascals. Unexpectedly, nanocrystalline CoAl intermetallics also show prominent work hardening to a flow stress of 5.7 gigapascals up to 20% compressive strain. Transmission electron microscopy studies show that deformation induces abundant dislocations inside CoAl grains with thick GBs, which accommodate plastic deformation. Molecular dynamics simulations reveal that the Co-rich thick GBs play a vital role in promoting nucleation of dislocations at the Co/CoAl interfaces, thereby enhancing the plasticity of the intermetallics. This study provides a perspective to promoting the plasticity of intermetallics via the introduction of thick GBs. read less R. Su et al., “Ultra-high strength and plasticity mediated by partial dislocations and defect networks: Part II: Layer thickness effect,” Acta Materialia. 2021. link Times cited: 7 P. Wang, Y. Bu, J. Liu, Q. Li, H. Wang, and W. Yang, “Atomic deformation mechanism and interface toughening in metastable high entropy alloy,” Materials Today. 2020. link Times cited: 41 R. Su et al., “Ultra-high strength and plasticity mediated by partial dislocations and defect networks: Part I: Texture effect,” Acta Materialia. 2020. link Times cited: 19 A. Sobolev, O. Golovnia, and A. Popov, “Embedded atom potential for Sm–Co compounds obtained by force-matching,” Journal of Magnetism and Magnetic Materials. 2019. link Times cited: 3 X. Lu, P. Yang, J. Luo, J. Ren, H. Xue, and Y. Ding, “Tensile mechanical performance of Ni–Co alloy nanowires by molecular dynamics simulation,” RSC Advances. 2019. link Times cited: 17 Abstract: In this present contribution, tensile mechanical properties … read more Abstract: In this present contribution, tensile mechanical properties of Ni–Co alloy nanowires with Co content from 0 to 20% were studied by molecular dynamics. The simulation results show the alloy nanowire with the Co content of 5% has the highest yield value of 9.72 GPa. In addition, more Frank dislocations were generated during the loading process to improve the performance of the alloy nanowire. The Young's modulus increases little by little from 105.68 to 179.78 GPa with the increase of Co content. Secondly, with the increase of temperature, the yield strength gradually decreases to 2.13 GPa. Young's modulus tends to decrease linearly from 170.7 GPa to 48.21 GPa. At the temperatures of 500 K and 700 K, it is easier to form Frank dislocation and Hirth dislocation, respectively, in the loading process. The peak value of the radial distribution function decreases and the number of peaks decreases, indicating the disappearance of the ordered structure. Finally, after the introduction of the surface and inner void, the yield strength of the nanowire drops about to 8.97 and 6.6 GPa, respectively, and the yield strains drop to 0.056 and 0.043. In the case of the existence of internal void, perfect dislocation and Hirth dislocation can be observed in the structure. read less D. Zhang and S. Chaudhuri, “Solidification dynamics and microstructure evolution in nanocrystalline cobalt,” Computational Materials Science. 2019. link Times cited: 8 R. Agrawal, P. Phatak, and L. Spanu, “Effect of phase and size on surface sites in cobalt nanoparticles,” Catalysis Today. 2018. link Times cited: 19 L. Béland et al., “Accurate classical short-range forces for the study of collision cascades in Fe-Ni-Cr,” Comput. Phys. Commun. 2017. link Times cited: 34 W. Wang, F. Yuan, P. Jiang, and X. Wu, “Size effects of lamellar twins on the strength and deformation mechanisms of nanocrystalline hcp cobalt,” Scientific Reports. 2017. link Times cited: 14 T. L. Achmad, W. Fu, H. Chen, C. Zhang, and Z.-G. Yang, “Effects of alloying elements concentrations and temperatures on the stacking fault energies of Co-based alloys by computational thermodynamic approach and first-principles calculations,” Journal of Alloys and Compounds. 2017. link Times cited: 45 Z. Wu and W. Curtin, “Mechanism and energetics of 〈c + a〉 dislocation cross-slip in hcp metals,” Proceedings of the National Academy of Sciences. 2016. link Times cited: 94 Abstract: Significance For all hexagonal close-packed (hcp) metals, th… read more Abstract: Significance For all hexagonal close-packed (hcp) metals, the ability to plastically deform in the crystallographic c axis is crucial for achieving high ductility and high fracture toughness. 〈c+a〉 dislocation slip is the only sustainable mechanism to accommodate c-axis strain, but is difficult across the family of hcp metals. We reveal the mechanism, energy barrier, and unusual stress dependence of 〈c+a〉 dislocation cross-slip in Mg, using atomistic simulations. Our results provide mechanistic insights into 〈c+a〉 cross-slip behavior, rationalize observed changes in pyramidal I/II slip stability, enable predictions of slip trends across the family of hcp metals, and suggest that applied stresses and/or precise solid solution alloying can optimize cross-slip and enhance c-axis strain capacity, which can ultimately guide design of improved hcp alloys. Hexagonal close-packed (hcp) metals such as Mg, Ti, and Zr are lightweight and/or durable metals with critical structural applications in the automotive (Mg), aerospace (Ti), and nuclear (Zr) industries. The hcp structure, however, brings significant complications in the mechanisms of plastic deformation, strengthening, and ductility, and these complications pose significant challenges in advancing the science and engineering of these metals. In hcp metals, generalized plasticity requires the activation of slip on pyramidal planes, but the structure, motion, and cross-slip of the associated 〈c+a〉 dislocations are not well established even though they determine ductility and influence strengthening. Here, atomistic simulations in Mg reveal the unusual mechanism of 〈c+a〉 dislocation cross-slip between pyramidal I and II planes, which occurs by cross-slip of the individual partial dislocations. The energy barrier is controlled by a fundamental step/jog energy and the near-core energy difference between pyramidal 〈c+a〉 dislocations. The near-core energy difference can be changed by nonglide stresses, leading to tension–compression asymmetry and even a switch in absolute stability from one glide plane to the other, both features observed experimentally in Mg, Ti, and their alloys. The unique cross-slip mechanism is governed by common features of the generalized stacking fault energy surfaces of hcp pyramidal planes and is thus expected to be generic to all hcp metals. An analytical model is developed to predict the cross-slip barrier as a function of the near-core energy difference and applied stresses and quantifies the controlling features of cross-slip and pyramidal I/II stability across the family of hcp metals. read less K. Xiong, Y. Zhang, and J. Gu, “Deformation Twinning in Hexagonal Close-Packed Single Crystals under Uniaxial Compression,” Materials Science Forum. 2016. link Times cited: 0 Abstract: In this paper, the uniaxial compression of Mg, Ti, Zr and Co… read more Abstract: In this paper, the uniaxial compression of Mg, Ti, Zr and Co single crystals along the direction is performed by molecular dynamics (MD) to investigate the elastic-to-plastic transition in these hexagonal close-packed (hcp) metals. Two deformation twinning modes are observed in these simulations, including the twinning in Ti, Zr and Co and the [0001] twinning in Mg. The underlying atomistic mechanisms of these twinning modes are analyzed in detail. read less L. Béland et al., “Features of primary damage by high energy displacement cascades in concentrated Ni-based alloys,” Journal of Applied Physics. 2016. link Times cited: 53 Abstract: Alloying of Ni with Fe or Co has been shown to reduce primar… read more Abstract: Alloying of Ni with Fe or Co has been shown to reduce primary damage production under ion irradiation. Similar results have been obtained from classical molecular dynamics simulations of 1, 10, 20, and 40 keV collision cascades in Ni, NiFe, and NiCo. In all cases, a mix of imperfect stacking fault tetrahedra, faulted loops with a 1/3⟨111⟩ Burgers vector, and glissile interstitial loops with a 1/2⟨110⟩ Burgers vector were formed, along with small sessile point defect complexes and clusters. Primary damage reduction occurs by three mechanisms. First, Ni-Co, Ni-Fe, Co-Co, and Fe-Fe short-distance repulsive interactions are stiffer than Ni-Ni interactions, which lead to a decrease in damage formation during the transition from the supersonic ballistic regime to the sonic regime. This largely controls final defect production. Second, alloying decreases thermal conductivity, leading to a longer thermal spike lifetime. The associated annealing reduces final damage production. These two mechanisms are especially ... read less K. Xiong, X. Liu, C. Li, and J. Gu, “Phonon instability of Co single crystal in uniaxial tension and nanoindentation,” Computational Materials Science. 2015. link Times cited: 8 W.-jin Zhang, Y. Peng, and Z.-L. Liu, “Molecular dynamics study of melting curve, entropy of fusion and solid-liquid interfacial energy of cobalt under pressure,” Physica B-condensed Matter. 2014. link Times cited: 10 C. Li, C. Ni, W. Zhou, X. Duan, and X. Jin, “Phase stability of Co nanowires prepared by electrodeposition via AAO templates,” Materials Letters. 2013. link Times cited: 8 P. Chowdhury and H. Sehitoglu, “Atomistic Fault Energetics and Critical Stress Prediction for fcc and bcc Twinning : Recent Progress AQ 3.” 2017. link Times cited: 10 Abstract: 15 This article recounts recent advances on the atomistic mo… read more Abstract: 15 This article recounts recent advances on the atomistic modeling of twinning in bcc and fcc alloy. Specifically, we have reviewed: (i) the experimental evidence of twinningdominated deformation in singleand multigrain microstructures (ii) calculation of generalized planar fault energy (GPFE) landscapes, and (iii) the prediction of critical friction stresses to initiate twinning-governed plasticity (e.g., twin nucleation, twin–slip and twin–twin interactions). Possible avenues for further research are outlined. [DOI: 10.1115/1.4038673] read less S. Dmitriev, A. Kistanov, and V. Dubinko, “Moving Discrete Breathers in 2D and 3D Crystals.” 2015. link Times cited: 8 S. Mukesh and N. Lanzillo, “A Multiscale Simulation Study of the Structural Integrity of Damascene Interconnects in Advanced Technology Nodes,” IEEE Transactions on Electron Devices. 2023. link Times cited: 0 Abstract: The structural stability of tight-pitched (18 nm and below) … read more Abstract: The structural stability of tight-pitched (18 nm and below) damascene interconnects for back-end-of-line (BEOL) technologies are analyzed using force-field-based molecular dynamics simulations and finite-element modeling. At these pitches surface energy-dominated effects come into the picture, which lead to structural instability. The candidate metals analyzed are beyond copper (Cu) interconnect metals-ruthenium (Ru), cobalt (Co), and tungsten (W); and Cu is analyzed for reference. Cohesive traction and normal bonding energy are calculated using force-field- based molecular dynamics simulations and then fed as input to a finite-element analysis (FEA) tool, where their dependence on the physical dimensions of the interconnect lines is studied. The parameters studied for the BEOL structures are sidewall angle, aspect ratio, the internal stress of the metal, and modulus of elasticity of the dielectric material around the metal to understand the sensitivity of these parameters to the structural stability of the interconnects. We observe that a lower aspect ratio and higher modulus of elasticity of the dielectric results in stable structures whereas, intrinsic stress of the metal and side wall angle have a minor impact on the overall stability. The stability is analyzed at the seed-layer deposition step and based on this study, Co is the most stable alternate metal amongst Ru, Co, and W. read less M. C. Kaymak, A. Rahnamoun, K. A. O’Hearn, A. V. van Duin, J. Kenneth M. Merz, and H. Aktulga, “JAX-ReaxFF: A Gradient Based Framework for Extremely Fast Optimization of Reactive Force Fields,” ChemRxiv. 2021. link Times cited: 1 Abstract: Molecular dynamics (MD) simulations facilitate the study of … read more Abstract: Molecular dynamics (MD) simulations facilitate the study of physical and chemical processes of interest. Traditional classical MD models lack reactivity to explore several important phenomena; while quantum mechanical (QM) models can be used for this purpose, they come with steep computational costs. The reactive force field (ReaxFF) model bridges the gap between these approaches by incorporating dynamic bonding and polarizability. To achieve realistic simulations using ReaxFF, model parameters must be optimized against high fidelity training data, typically with QM accuracy. Existing parameter optimization methods for ReaxFF consist of black-box techniques using genetic algorithms or Monte-Carlo methods. Due to the stochastic behavior of these methods, the optimization process can require millions of error evaluations for complex parameter fitting tasks, significantly hampering the rapid development of high quality parameter sets. In this work, we present JAX ReaxFF, a novel software tool that leverages modern machine learning infrastructure to enable extremely fast optimization of ReaxFF parameters. By calculating gradients of the loss function using the JAX library, we are able to utilize highly effective local optimization methods, such as the limited Broyden–Fletcher–Goldfarb–Shanno (LBFGS) and Sequential Least Squares Programming (SLSQP) methods. As a result of the performance portability of JAX, JAX-ReaxFF can execute efficiently on multi-core CPUs, GPUs (or even TPUs). By leveraging the gradient information and modern hardware accelerators, we are able to decrease parameter optimization time for ReaxFF from days to mere minutes. JAX-ReaxFF framework can also serve as a sandbox environment for domain scientists to explore customizing the ReaxFF functional form for more accurate modeling. read less J. Tong et al., “Interfacial antiferromagnetic coupling and high spin polarization in metallic phthalocyanines,” Physical Review B. 2021. link Times cited: 3 Abstract: Exploration and understanding of the spinterface between mag… read more Abstract: Exploration and understanding of the spinterface between magnetic electrodes and organic semiconductors are vital to get an insight into interfacial science and develop spintronic devices. Intrigued by the fact that the modification of chemical states may affect interfacial exchange coupling, magnetic interactions between a series of metallic phthalocyanines ($M\mathrm{Pcs}, M=\mathrm{Cr}$, Mn, Fe, Co) and surface oxidized Co were studied. Interestingly, these four $M\mathrm{Pcs}$ are all antiferromagnetically coupled with the Co substrate via the interfacial O atomic layer, but the coupling strength strongly relies on the type of metallic ion in the $M\mathrm{Pcs}$. The physical mechanism for different exchange strengths is explored and discussed in terms of a superexchange model via O atoms. It is also noted that the adsorption energy and work function of the surface oxidized Co were sensitive to the metallic ions of $M\mathrm{Pcs}$. The valence and spin state of central $3d$ metallic ions could be tuned by the surface oxidized Co. Very interestingly, high negative spin-polarized spinterfaces are obtained in these $M\mathrm{Pcs}$. The spin polarizations are up to \ensuremath{-}86% and \ensuremath{-}80% for CrPc and MnPc, respectively. Additionally, high spin polarization can be maintained beyond room temperature because of the very large interfacial coupling energy, demonstrating a promising application of $M\mathrm{Pcs}$ in spintronic devices. read less J. Fürnkranz, “Publication list,” Journal of Physics: Conference Series. 2019. link Times cited: 10 Abstract: PUBLICATION LIST of VICTOR MANUEL VILLANUEVA SANDOVAL availa… read more Abstract: PUBLICATION LIST of VICTOR MANUEL VILLANUEVA SANDOVAL available in this PDF. read less J. Qi, C. Oberdorfer, W. Windl, and E. Marquis, “Ab initio simulation of field evaporation,” Physical Review Materials. 2022. link Times cited: 5 Abstract: A new simulation approach of field evaporation is presented.… read more Abstract: A new simulation approach of field evaporation is presented. The model combines classical electrostatics with molecular dynamics (MD) simulations. Unlike previous atomic-level simulation approaches, our method does not rely on an evaporation criterion based on thermal activation theory, instead, electric-field-induced forces on atoms are explicitly calculated and added to the interatomic forces. Atoms then simply move according to the laws of classical molecular dynamics and are"evaporated"when the external force overcomes interatomic bonding. This approach thus makes no ad-hoc assumptions concerning evaporation fields and criteria, which makes the simulation fully physics-based and"ab-initio"apart from the interatomic potential. As proof of principle, we perform simulations to determine material dependent critical voltages which allow assessing the evaporation fields and the corresponding steady-state tip shapes in different metals. We also extract critical evaporation fields in elemental metals and sublimation energies in a high entropy alloy to have a more direct comparison with tabulated values. In contrast to previous approaches, we show that our method is able to successfully reproduce the enhanced zone lines observed in experimental field desorption patterns. We also demonstrate the need for careful selection of the interatomic potential by a comparative study for the example of Cu-Ni alloys. read less M. Gu, Y. Bai, G. Zhang, and T. George, “Spin–phonon dispersion in magnetic materials,” Journal of Physics: Condensed Matter. 2022. link Times cited: 2 Abstract: Microscopic coupling between the electron spin and the latti… read more Abstract: Microscopic coupling between the electron spin and the lattice vibration is responsible for an array of exotic properties from morphic effects in simple non magnets to magnetodielectric coupling in multiferroic spinels and hematites. Traditionally, a single spin–phonon coupling constant is used to characterize how effectively the lattice can affect the spin, but it is hardly enough to capture novel electromagnetic behaviors to the full extent. Here, we introduce a concept of spin–phonon dispersion to project the spin moment change along the phonon crystal momentum direction, so the entire spin change can be mapped out. Different from the phonon dispersion, the spin–phonon dispersion has both positive and negative frequency branches even in the equilibrium ground state, which correspond to the spin enhancement and spin reduction, respectively. Our study of bcc Fe and hcp Co reveals that the spin force matrix, that is, the second-order spatial derivative of spin moment, is similar to the vibrational force matrix, but its diagonal elements are smaller than the off-diagonal ones. This leads to the distinctive spin–phonon dispersion. The concept of spin–phonon dispersion expands the traditional Elliott-Yafet theory in nonmagnetic materials to the entire Brillouin zone in magnetic materials, thus opening the door to excited states in systems such as CoF2 and NiO, where a strong spin-lattice coupling is detected in the THz regime. read less K. Kowalczyk-Gajewska and M. Ma’zdziarz, “Elastic properties of nanocrystalline materials of hexagonal symmetry: The core-shell model and atomistic estimates,” International Journal of Engineering Science. 2020. link Times cited: 5 J. Martí and B. Díaz, “Efficient recursive Adams–Bashforth methods in molecular dynamics simulations of N-body systems interacting through pairwise potentials,” Molecular Simulation. 2020. link Times cited: 1 Abstract: ABSTRACT A recursive multistep Adams–Bashforth method applie… read more Abstract: ABSTRACT A recursive multistep Adams–Bashforth method applied to the Molecular Dynamics simulations of N-body systems interacting through pairwise force fields is introduced and analysed. Equations of motion are obtained using a set of Cartesian coordinates solved by means of an Adams–Bashforth numerical integration scheme of order s, which requires the iterative computation of function time derivatives. The proposed algorithm has been implemented using a programming approach that makes it possible to re-use a source code resulting in small codes, easy to maintain. Practical examples and benchmarks that illustrate the performance of these implementations are included. The study of its performance gives clues to evaluate its efficiency and precision. Numerical tests for a N-particle system are made on the equilibrium configuration of liquid argon near its triple point at 86.5 K and 0.021 Å . In most cases, the algorithms here presented outperform those implemented traditionally as the Gear corrector-predictor or the Verlet family, leading to important savings in terms of total computation times and significantly increasing the numerical precision obtained with standard algorithms. read less M. Vallone, “Structural Phase Transitions in Crystals: Phonons as Higgs and Goldstone Excitations,” physica status solidi (RRL) – Rapid Research Letters. 2020. link Times cited: 0 Abstract: It has recently been indicated that optical and acoustic pho… read more Abstract: It has recently been indicated that optical and acoustic phonons can be identified with Higgs and Goldstone excitations of the crystal lattice arising from the spontaneous breaking of a global, continuous symmetry. Herein, this view is supported considering structural phase transitions induced by temperature, from the face‐centered‐cubic (fcc) phase of cobalt, and from the body‐centered‐cubic (bcc) phase of zirconium and titanium, to their hexagonal‐close‐packet (hcp) phase. The Higgs field potential is identified with the Ginzburg–Landau free energy difference calculated and available in the literature for the concerned structural phase transitions. In all the considered cases, the ensuing spontaneous symmetry breaking makes the optical phonon (identified with the Higgs mode) to arise only in the less symmetric hcp phase. This demonstrates Higgs excitations to be associated not only with quantum phase transitions, but also with structural phase transitions in natural crystals. read less Y. M. Gufan, O. V. Naskalova, O. V. Kukin, and G. V. Fomin, “Symmetry Of Irreducible Cluster Energy And The Theory Of Elastic Constant Crystals: Co as an Example.” 2018. link Times cited: 0 Abstract: The paper proposes a new method of transferable calculation… read more Abstract: The paper proposes a new method of transferable calculation of elastic constants of the second, third and fourth orders. The method is based on the assumption that the potential energy of bulk crystals may be presented as the decomposition into irreducible energies of two, three, and four atomic clusters. To justify this decomposition, we proved that the irreducible energy of atomic clusters obeys additional symmetry O3×NCl, which depends on the number of atoms constituting clusters (NCl), and not depends on cluster structure. Additional symmetry allows defining the bases invariants, which depend on interatomic distances, and irreducible energies of clusters are depended on bases invariants only. In turn, these dependences made it possible to calculate the elastic modulus of complexes that exist in different crystal modifications as functions of the same phenomenological parameters of the model of interatomic interactions. Then we presented an example of the calculation of elastic constants BCC, HCP and FCC of the metal phases of Co polymorphs. The results confirm that the proposed method is transferable and makes it possible to calculate the elastic moduli of the second, third and fourth orders with the accuracy not worse than was achieved using the quantum chemistry models. Keywordselastic moduli, Cauchy ratio, irreducible read less R. Khusnutdinoff, A. Mokshin, A. L. Bel’tyukov, and N. Olyanina, “Viscosity of Cobalt Melt: Experiment, Simulation, and Theory,” High Temperature. 2018. link Times cited: 5 P. Chowdhury and H. Sehitoglu, “Atomistic Energetics and Critical Twinning Stress Prediction in Face and Body Centered Cubic Metals: Recent Progress,” Journal of Engineering Materials and Technology-transactions of The Asme. 2018. link Times cited: 19 Abstract: This paper recounts recent advances on the atomistic modelin… read more Abstract: This paper recounts recent advances on the atomistic modeling of twinning in bodycentered cubic (bcc) and face-centered cubic (fcc) alloy. Specifically, we have reviewed: (i) the experimental evidence of twinning-dominated deformation in singleand multigrain microstructures, (ii) calculation of generalized planar fault energy (GPFE) landscapes, and (iii) the prediction of critical friction stresses to initiate twinning-governed plasticity (e.g., twin nucleation, twin–slip and twin–twin interactions). Possible avenues for further research are outlined. [DOI: 10.1115/1.4038673] read less W. Wang, P. Jiang, F. Yuan, and X. Wu, “Size effects of nano-spaced basal stacking faults on the strength and deformation mechanisms of nanocrystalline pure hcp metals,” Philosophical Magazine. 2018. link Times cited: 5 Abstract: The size effects of nano-spaced basal stacking faults (SFs) … read more Abstract: The size effects of nano-spaced basal stacking faults (SFs) on the tensile strength and deformation mechanisms of nanocrystalline pure cobalt and magnesium have been investigated by a series of large-scale 2D columnar and 3D molecular dynamics simulations. Unlike the strengthening effect of basal SFs on Mg alloys, the nano-spaced basal SFs are observed to have no strengthening effect on the nanocrystalline pure cobalt and magnesium from MD simulations. These observations could be attributed to the following two reasons: (i) Lots of new basal SFs are formed before (for cobalt) or simultaneously with (for magnesium) the other deformation mechanisms (i.e. the formation of twins and the < c + a > edge dislocations) during the tensile deformation; (ii) In hcp alloys, the segregation of alloy elements and impurities at typical interfaces, such as SFs, can stablilise them for enhancing the interactions with dislocation and thus elevating the strength. Without such segregation in pure hcp metals, the < c + a > edge dislocations can cut through the basal SFs although the interactions between the < c + a > dislocations and the pre-existing SFs/newly formed SFs are observed. The nano-spaced basal SFs are also found to have no restriction effect on the formation of deformation twins. read less B. Cheng and M. Ceriotti, “Computing the absolute Gibbs free energy in atomistic simulations: Applications to defects in solids,” Physical Review B. 2017. link Times cited: 40 Abstract: The Gibbs free energy is the fundamental thermodynamic poten… read more Abstract: The Gibbs free energy is the fundamental thermodynamic potential underlying the relative stability of different states of matter under constant-pressure conditions. However, computing this quantity from atomic-scale simulations is far from trivial. As a consequence, all too often the potential energy of the system is used as a proxy, overlooking entropic and anharmonic effects. Here we discuss a combination of different thermodynamic integration routes to obtain the absolute Gibbs free energy of a solid system starting from a harmonic reference state. This approach enables the direct comparison between the free energy of different structures, circumventing the need to sample the transition paths between them. We showcase this thermodynamic integration scheme by computing the Gibbs free energy associated with a vacancy in BCC iron, and the intrinsic stacking fault free energy of nickel. These examples highlight the pitfalls of estimating the free energy of crystallographic defects only using the minimum potential energy, which overestimates the vacancy free energy by 60% and the stacking-fault energy by almost 300% at temperatures close to the melting point. read less M. Mattheakis, M. Mattheakis, M. Mattheakis, G. Tsironis, G. Tsironis, and G. Tsironis, “Quodons in Mica: Nonlinear Localized Travelling Excitations in Crystals,” Quodons in Mica. 2017. link Times cited: 24 Y. Wang et al., “Precursor-directed synthesis of porous cobalt assemblies with tunable close-packed hexagonal and face-centered cubic phases for the effective enhancement in microwave absorption,” Journal of Materials Science. 2017. link Times cited: 30 B. Molaei and S. A. Kahani, “Synthesis of cobalt-based magnetic nanocrystals from cobalt(II) heterocyclic amine complexes,” Research on Chemical Intermediates. 2017. link Times cited: 0 R. Babicheva et al., “Elastic moduli of nanocrystalline binary Al alloys with Fe, Co, Ti, Mg and Pb alloying elements,” Philosophical Magazine. 2016. link Times cited: 13 Abstract: The paper studies the elastic moduli of nanocrystalline (NC)… read more Abstract: The paper studies the elastic moduli of nanocrystalline (NC) Al and NC binary Al–X alloys (X is Fe, Co, Ti, Mg or Pb) by using molecular dynamics simulations. X atoms in the alloys are either segregated to grain boundaries (GBs) or distributed randomly as in disordered solid solution. At 0 K, the rigidity of the alloys increases with decrease in atomic radii of the alloying elements. An addition of Fe, Co or Ti to the NC Al leads to increase in the Young’s E and shear μ moduli, while an alloying with Pb decreases them. The elastic moduli of the alloys depend on a distribution of the alloying elements. The alloys with the random distribution of Fe or Ti demonstrate larger E and μ than those for the corresponding alloys with GB segregations, while the rigidity of the Al–Co alloy is higher for the case of the GB segregations. The moduli E and μ for polycrystalline aggregates of Al and Al–X alloys with randomly distributed X atoms are estimated based on the elastic constants of corresponding single-crystals according to the Voigt-Reuss-Hill approximation, which neglects the contribution of GBs to the rigidity. The results show that GBs in NC materials noticeably reduce their rigidity. Furthermore, the temperature dependence of μ for the NC Al–X alloys is analyzed. Only the Al–Co alloy with GB segregations shows the decrease in μ to the lowest extent in the temperature range of 0–600 K in comparison with the NC pure Al. read less P. Chowdhury, H. Sehitoglu, H. Maier, and R. Rateick, “Strength prediction in NiCo alloys - The role of composition and nanotwins,” International Journal of Plasticity. 2016. link Times cited: 58 V. Yamakov et al., “Multiscale modeling of sensory properties of Co–Ni–Al shape memory particles embedded in an Al metal matrix,” Journal of Materials Science. 2016. link Times cited: 24 K. Zhang, M. Fan, Y. Liu, J. Schroers, M. Shattuck, and C. O’Hern, “Beyond packing of hard spheres: The effects of core softness, non-additivity, intermediate-range repulsion, and many-body interactions on the glass-forming ability of bulk metallic glasses.,” The Journal of chemical physics. 2015. link Times cited: 16 Abstract: When a liquid is cooled well below its melting temperature a… read more Abstract: When a liquid is cooled well below its melting temperature at a rate that exceeds the critical cooling rate Rc, the crystalline state is bypassed and a metastable, amorphous glassy state forms instead. Rc (or the corresponding critical casting thickness dc) characterizes the glass-forming ability (GFA) of each material. While silica is an excellent glass-former with small Rc < 10(-2) K/s, pure metals and most alloys are typically poor glass-formers with large Rc > 10(10) K/s. Only in the past thirty years have bulk metallic glasses (BMGs) been identified with Rc approaching that for silica. Recent simulations have shown that simple, hard-sphere models are able to identify the atomic size ratio and number fraction regime where BMGs exist with critical cooling rates more than 13 orders of magnitude smaller than those for pure metals. However, there are a number of other features of interatomic potentials beyond hard-core interactions. How do these other features affect the glass-forming ability of BMGs? In this manuscript, we perform molecular dynamics simulations to determine how variations in the softness and non-additivity of the repulsive core and form of the interatomic pair potential at intermediate distances affect the GFA of binary alloys. These variations in the interatomic pair potential allow us to introduce geometric frustration and change the crystal phases that compete with glass formation. We also investigate the effect of tuning the strength of the many-body interactions from zero to the full embedded atom model on the GFA for pure metals. We then employ the full embedded atom model for binary BMGs and show that hard-core interactions play the dominant role in setting the GFA of alloys, while other features of the interatomic potential only change the GFA by one to two orders of magnitude. Despite their perturbative effect, understanding the detailed form of the intermetallic potential is important for designing BMGs with cm or greater casting thickness. read less G. P. P. Pun, V. Yamakov, and Y. Mishin, “Interatomic potential for the ternary Ni–Al–Co system and application to atomistic modeling of the B2–L10 martensitic transformation,” Modelling and Simulation in Materials Science and Engineering. 2015. link Times cited: 80 Abstract: Ni–Al–Co is a promising system for ferromagnetic shape memor… read more Abstract: Ni–Al–Co is a promising system for ferromagnetic shape memory applications. This paper reports on the development of a ternary embedded-atom potential for this system by fitting to experimental and first-principles data. Reasonably good agreement is achieved for physical properties between values predicted by the potential and values known from experiment and/or first-principles calculations. The potential reproduces basic features of the martensitic phase transformation from the B2-ordered high-temperature phase to a tetragonal CuAu-ordered low-temperature phase. The compositional and temperature ranges of this transformation and the martensite microstructure predicted by the potential compare well with existing experimental data. These results indicate that the proposed potential can be used for simulations of the shape memory effect in the Ni–Al–Co system. read less S. Schonecker, X. Li, K. Koepernik, B. Johansson, L. Vitos, and M. Richter, “Metastable cubic and tetragonal phases of transition metals predicted by density-functional theory,” RSC Advances. 2015. link Times cited: 9 Abstract: By means of density-functional calculations, we systematical… read more Abstract: By means of density-functional calculations, we systematically investigated 24 transition metals for possible metastable phases in body-centered tetragonal structure (bct), including face-centered ... read less H. Yoon et al., “In situ non-aqueous nucleation and growth of next generation rare-earth-free permanent magnets.,” Physical chemistry chemical physics : PCCP. 2015. link Times cited: 23 Abstract: Using a controllable wet chemical approach, the polyol proce… read more Abstract: Using a controllable wet chemical approach, the polyol process, we developed a cobalt carbide nanomagnet consisting of an assembly of Co2C and Co3C nanoparticles as an alternative to rare earth permanent magnets (PMs). The thermodynamically stable mixed phase cobalt carbide nanoparticles are shown to be acicular in morphology. Their exchange-coupled magnetic interaction possessing high maximum energy product of 20.7 kJ m(-3) and room temperature coercivity (2.9 kOe) has been confirmed through vibrating sample magnetometer (VSM) and first order reversal curves (FORCs). These metastable carbide nanoparticles offer improved magnetic properties compared to their pure bulk form. An understanding of the formation mechanism, using in situ time-resolved X-ray spectroscopy (TR-XAS), and the correlation between phase contributions to the properties are described in detail. Our strategy presents a controllable route to preparing the cobalt carbide nanomagnets, which could be potentially useful in permanent magnet clean energy applications. Additionally, the in situ apparatus offers a promising way to directly explore the effects of reaction variables for high-temperature wet chemical reactions. read less D. Geissler, J. Freudenberger, A. Kauffmann, S. Martin, and D. Rafaja, “Assessment of the thermodynamic dimension of the stacking fault energy,” Philosophical Magazine. 2014. link Times cited: 21 Abstract: Especially with respect to high Mn and other austenitic TRan… read more Abstract: Especially with respect to high Mn and other austenitic TRansformation and/or TWinning Induced Plasticity (TRIP/TWIP) steels, it is a current trend to model the stacking fault energy of a stacking fault that is formed by plastic deformation with an equilibrium thermodynamic formalism as proposed by Olson and Cohen in 1976. In the present paper, this formalism is critically discussed and its ambiguity is stressed. Suggestions are made, how the stacking fault energy and its relation to the formation of hexagonal ϵ-martensite might be treated appropriately. It is further emphasized that a thermodynamic treatment of deformation-induced stacking fault phenomena always faces some ambiguity. However, an alternative thermodynamic approach to stacking faults, twinning and the formation of ϵ-martensite in austenitic steels might rationalize the specific stacking fault arrangements encountered during deformation of TRIP/TWIP alloys. read less S. Meher, P. Nandwana, T. Rojhirunsakool, J. Tiley, and R. Banerjee, “Probing the crystallography of ordered Phases by coupling of orientation microscopy with atom probe tomography.,” Ultramicroscopy. 2015. link Times cited: 17
Funding	Not available

Short KIM ID The unique KIM identifier code.	MO_885079680379_005
Extended KIM ID The long form of the KIM ID including a human readable prefix (100 characters max), two underscores, and the Short KIM ID. Extended KIM IDs can only contain alpha-numeric characters (letters and digits) and underscores and must begin with a letter.	EAM_Dynamo_PunMishin_2012_Co__MO_885079680379_005
DOI	10.25950/8d5b6ade https://doi.org/10.25950/8d5b6ade https://commons.datacite.org/doi.org/10.25950/8d5b6ade
KIM Item Type Specifies whether this is a Portable Model (software implementation of an interatomic model); Portable Model with parameter file (parameter file to be read in by a Model Driver); Model Driver (software implementation of an interatomic model that reads in parameters).	Portable Model using Model Driver EAM_Dynamo__MD_120291908751_005
Driver	EAM_Dynamo__MD_120291908751_005
KIM API Version	2.0
Potential Type	eam

Previous Version	EAM_Dynamo_PunMishin_2012_Co__MO_885079680379_004

Verification Check Dashboard

(Click here to learn more about Verification Checks)

Grade	Name	Category	Brief Description	Full Results	Aux File(s)
P All elements claimed by model are supported in at least one of the tested configurations.	vc-species-supported-as-stated	mandatory	The model supports all species it claims to support; see full description.	Results	Files
P Periodic boundary conditions were correctly supported for all configurations that the model was able to compute.	vc-periodicity-support	mandatory	Periodic boundary conditions are handled correctly; see full description.	Results	Files
P Model energy has permutation symmetry for all configurations the model was able to compute.	vc-permutation-symmetry	mandatory	Total energy and forces are unchanged when swapping atoms of the same species; see full description.	Results	Files
A The letter grade A was assigned because the normalized error in the computation was 1.99081e-09 compared with a machine precision of 2.22045e-16. The letter grade was based on 'score=log10(error/eps)', with ranges A=[0, 7.5], B=(7.5, 10.0], C=(10.0, 12.5], D=(12.5, 15.0), F>15.0. 'A' is the best grade, and 'F' indicates failure.	vc-forces-numerical-derivative	consistency	Forces computed by the model agree with numerical derivatives of the energy; see full description.	Results	Files
F The model is C^0 continuous. This means that the model has continuous energy, but a discontinuous first derivative.	vc-dimer-continuity-c1	informational	The energy versus separation relation of a pair of atoms is C1 continuous (i.e. the function and its first derivative are continuous); see full description.	Results	Files
P Model energy and forces are invariant with respect to rigid-body motion (translation and rotation) for all configurations the model was able to compute.	vc-objectivity	informational	Total energy is unchanged and forces transform correctly under rigid-body translation and rotation; see full description.	Results	Files
P Model energy has inversion symmetry for all configurations the model was able to compute.	vc-inversion-symmetry	informational	Total energy is unchanged and forces change sign when inverting a configuration through the origin; see full description.	Results	Files
P No memory leak detected.	vc-memory-leak	informational	The model code does not have memory leaks (i.e. it releases all allocated memory at the end); see full description.	Results	Files
P All threads give identical results for tested case. Model appears to be thread-safe.	vc-thread-safe	mandatory	The model returns the same energy and forces when computed in serial and when using parallel threads for a set of configurations. Note that this is not a guarantee of thread safety; see full description.	Results	Files
P Unit conversion successful	vc-unit-conversion	mandatory	The model is able to correctly convert its energy and/or forces to different unit sets; see full description.	Results	Files

This bar chart plot shows the mono-atomic body-centered cubic (bcc) lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Co

Cohesive Energy Graph

This graph shows the cohesive energy versus volume-per-atom for the current mode for four mono-atomic cubic phases (body-centered cubic (bcc), face-centered cubic (fcc), simple cubic (sc), and diamond). The curve with the lowest minimum is the ground state of the crystal if stable. (The crystal structure is enforced in these calculations, so the phase may not be stable.) Graphs are generated for each species supported by the model.

Species: Co

Diamond Lattice Constant

This bar chart plot shows the mono-atomic face-centered diamond lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Co

Dislocation Core Energies

This graph shows the dislocation core energy of a cubic crystal at zero temperature and pressure for a specific set of dislocation core cutoff radii. After obtaining the total energy of the system from conjugate gradient minimizations, non-singular, isotropic and anisotropic elasticity are applied to obtain the dislocation core energy for each of these supercells with different dipole distances. Graphs are generated for each species supported by the model.

(No matching species)

FCC Elastic Constants

This bar chart plot shows the mono-atomic face-centered cubic (fcc) elastic constants predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Co

FCC Lattice Constant

This bar chart plot shows the mono-atomic face-centered cubic (fcc) lattice constant predicted by the current model (shown in red) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Co

FCC Stacking Fault Energies

This bar chart plot shows the intrinsic and extrinsic stacking fault energies as well as the unstable stacking and unstable twinning energies for face-centered cubic (fcc) predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

FCC Surface Energies

This bar chart plot shows the mono-atomic face-centered cubic (fcc) relaxed surface energies predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

SC Lattice Constant

This bar chart plot shows the mono-atomic simple cubic (sc) lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Co

Cubic Crystal Basic Properties Table

Species: Co

Tests

Disclaimer From Model Developer

The potential accurately represents most of the properties of the hcp and the fcc phases of Co including the phase transition temperature.

CohesiveEnergyVsLatticeConstant__TD_554653289799_003

Cohesive energy versus lattice constant curve for monoatomic cubic lattices v003

Creators:
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/64cb38c5

This Test Driver uses LAMMPS to compute the cohesive energy of a given monoatomic cubic lattice (fcc, bcc, sc, or diamond) at a variety of lattice spacings. The lattice spacings range from a_min (=a_min_frac*a_0) to a_max (=a_max_frac*a_0) where a_0, a_min_frac, and a_max_frac are read from stdin (a_0 is typically approximately equal to the equilibrium lattice constant). The precise scaling and number of lattice spacings sampled between a_min and a_0 (a_0 and a_max) is specified by two additional parameters passed from stdin: N_lower and samplespacing_lower (N_upper and samplespacing_upper). Please see README.txt for further details.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Cohesive energy versus lattice constant curve for bcc Co v004	view	9318
Cohesive energy versus lattice constant curve for diamond Co v004	view	7798
Cohesive energy versus lattice constant curve for fcc Co v004	view	8393
Cohesive energy versus lattice constant curve for sc Co v004	view	8393

ElasticConstantsCubic__TD_011862047401_006

Elastic constants for cubic crystals at zero temperature and pressure v006

Creators: Junhao Li and Ellad Tadmor
Contributor: tadmor
Publication Year: 2019
DOI: https://doi.org/10.25950/5853fb8f

Computes the cubic elastic constants for some common crystal types (fcc, bcc, sc, diamond) by calculating the hessian of the energy density with respect to strain. An estimate of the error associated with the numerical differentiation performed is reported.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for bcc Co at zero temperature v006	view	6238
Elastic constants for diamond Co at zero temperature v001	view	11356
Elastic constants for fcc Co at zero temperature v006	view	4031
Elastic constants for sc Co at zero temperature v006	view	2207

ElasticConstantsHexagonal__TD_612503193866_004

Elastic constants for hexagonal crystals at zero temperature v004

Creators: Junhao Li
Contributor: jl2922
Publication Year: 2019
DOI: https://doi.org/10.25950/d794c746

Computes the elastic constants for hcp crystals by calculating the hessian of the energy density with respect to strain. An estimate of the error associated with the numerical differentiation performed is reported.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for hcp Co at zero temperature v004		view	2069

EquilibriumCrystalStructure__TD_457028483760_002

Equilibrium structure and energy for a crystal structure at zero temperature and pressure v002

Creators:
Contributor: ilia
Publication Year: 2024
DOI: https://doi.org/10.25950/2f2c4ad3

Computes the equilibrium crystal structure and energy for an arbitrary crystal at zero temperature and applied stress by performing symmetry-constrained relaxation. The crystal structure is specified using the AFLOW prototype designation. Multiple sets of free parameters corresponding to the crystal prototype may be specified as initial guesses for structure optimization. No guarantee is made regarding the stability of computed equilibria, nor that any are the ground state.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium crystal structure and energy for Co in AFLOW crystal prototype A_cF4_225_a v002	view	93056
Equilibrium crystal structure and energy for Co in AFLOW crystal prototype A_hP2_194_c v002	view	73989
Equilibrium crystal structure and energy for Co in AFLOW crystal prototype A_tI2_139_a v002	view	46299
Equilibrium crystal structure and energy for Co in AFLOW crystal prototype A_tP28_136_f2ij v002	view	147683

LatticeConstantCubicEnergy__TD_475411767977_007

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure v007

Creators: Daniel S. Karls and Junhao Li
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/2765e3bf

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium zero-temperature lattice constant for bcc Co v007	view	1855
Equilibrium zero-temperature lattice constant for diamond Co v007	view	3679
Equilibrium zero-temperature lattice constant for fcc Co v007	view	3775
Equilibrium zero-temperature lattice constant for sc Co v007	view	2495

LatticeConstantHexagonalEnergy__TD_942334626465_005

Equilibrium lattice constants for hexagonal bulk structures at zero temperature and pressure v005

Creators: Daniel S. Karls and Junhao Li
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/c339ca32

Calculates lattice constant of hexagonal bulk structures at zero temperature and pressure by using simplex minimization to minimize the potential energy.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium lattice constants for hcp Co v005		view	28493

VacancyFormationEnergyRelaxationVolume__TD_647413317626_001

Monovacancy formation energy and relaxation volume for cubic and hcp monoatomic crystals v001

Creators:
Contributor: efuem
Publication Year: 2023
DOI: https://doi.org/10.25950/fca89cea

Computes the monovacancy formation energy and relaxation volume for cubic and hcp monoatomic crystals.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Monovacancy formation energy and relaxation volume for hcp Co		view	439662

VacancyFormationMigration__TD_554849987965_001

Vacancy formation and migration energies for cubic and hcp monoatomic crystals v001

Creators:
Contributor: efuem
Publication Year: 2023
DOI: https://doi.org/10.25950/c27ba3cd

Computes the monovacancy formation and migration energies for cubic and hcp monoatomic crystals.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Vacancy formation and migration energy for hcp Co		view	2903151

Errors

EquilibriumCrystalStructure__TD_457028483760_000

Test	Error Categories	Link to Error page
Equilibrium crystal structure and energy for Co in AFLOW crystal prototype A_tP28_136_f2ij v000	other	view

EquilibriumCrystalStructure__TD_457028483760_002

Test	Error Categories	Link to Error page
Equilibrium crystal structure and energy for Co in AFLOW crystal prototype A_oC4_63_c v002	other	view

LatticeConstantCubicEnergy__TD_475411767977_006

Test	Error Categories	Link to Error page
Equilibrium zero-temperature lattice constant for diamond Co	other	view

Files

CMakeLists.txt
Co_PurjaPun_2012.eam.alloy
LICENSE.CDDL
kimprovenance.edn
kimspec.edn

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EAM_Dynamo_PunMishin_2012_Co__MO_885079680379_005

Verification Check Dashboard

Visualizers (in-page)

BCC Lattice Constant

Cohesive Energy Graph

Diamond Lattice Constant

Dislocation Core Energies

FCC Elastic Constants

FCC Lattice Constant

FCC Stacking Fault Energies

FCC Surface Energies

SC Lattice Constant

Cubic Crystal Basic Properties Table

Tests

Disclaimer From Model Developer

Errors

Files

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