Select a Property Definition


See the KIM Properties Framework for more detailed information.


DefinitionTitleDescriptionTest Results
atomic-mass Atomic mass The atomic mass of the element No Results
binding-energy-crystal Equilibrium crystal structure and binding potential energy at zero temperature and applied stress Equilibrium structure and energy of a crystal at zero temperature and applied stress. The equilibrium structure is expressed as an AFLOW prototype label and its corresponding free parameters. The equilibrium may be stable or unstable (not reported in this property). Multiple instances of this property with different free parameters may be reported for a given AFLOW prototype label, representing different stable or unstable equilibria. There is no guarantee that any instance of this property is the ground state of this system, not even when the configuration space is restricted to the specified crystal prototype label.


The reported binding potential energy is the energy required to decompose the solid into its individual constituent particles isolated from each other. This is defined as the energy of the crystal less the energies of the isolated constituent particles.


Two values are reported, the `binding-potential-energy-per-atom` is the average energy per atom in the unit cell, the `binding-potential-energy-per-formula` is the energy per chemical formula, which reflects the relative ratio of elements in the primitive unit cell of the crystal. For a crystal containing a single chemical element (regardless of structure) this is the same as the `binding-potential-energy-per-atom`, e.g. for hcp Mg the chemical formula is Mg and the 'binding-potential-energy-per-formula' is per magnesium atom (even though the hcp primitive unit cell contains two atoms). For compounds the 'binding-potential-energy-per-formula' will depend on the stoichiometric formula, e.g. for MoS_2 (AB2-type compound) the energy is per MoS_2 unit (i.e. 3 times larger than the `binding-potential-energy-per-atom` value). The reported energies are actual energies (not the negative of the energy as commonly reported), therefore these values will be negative for a crystal that is more stable than its isolated constituents.
Results 220
bulk-modulus-isothermal-cubic-crystal-npt Isothermal bulk modulus of a cubic crystal at constant temperature and hydrostatic stress Isothermal bulk modulus of a cubic crystal at constant temperature and hydrostatic stress. Results 2967
bulk-modulus-isothermal-hexagonal-crystal-npt Isothermal bulk modulus of a hexagonal crystal structure at constant temperature and stress Isothermal bulk modulus of a hexagonal crystal structure at constant temperature and stress. Results 352
cohesive-energy-lattice-invariant-shear-path-cubic-crystal Cohesive energy for a lattice-invariant shear path deformation of a cubic crystal Cohesive energy versus shear relation along a lattice-invariant deformation path of a cubic crystal at zero absolute temperature. The lattice-invariant shear path is defined by a shearing direction and shear plane normal relative to the reference conventional crystal coordinate system. All primitive unit cell atomic shifts are energy minimized for each value of the shear parameter. Results 2
cohesive-energy-lattice-invariant-shear-unrelaxed-path-cubic-crystal Cohesive energy for an unrelaxed lattice-invariant shear path deformation of a cubic crystal Unrelaxed cohesive energy versus shear relation along a lattice-invariant deformation path of a cubic crystal at zero absolute temperature. The lattice-invariant shear path is defined by a shearing direction and shear plane normal relative to the reference conventional crystal coordinate system. Unit cell atomic shifts are NOT minimized for each value of the shear parameter. No Results
cohesive-energy-relation-cubic-crystal Cohesive energy versus lattice constant relation for a cubic crystal Cohesive energy versus lattice constant relation for a cubic crystal at zero absolute temperature. Lattice constants are taken to correspond to the conventional cubic unit cell. Moreover, note that here the cohesive energy is defined as the *negative* of the potential energy per atom. Results 3346
cohesive-energy-shear-stress-path-cubic-crystal Cohesive energy and stability versus first Piola-Kirchhoff shear stress path of a cubic crystal Cohesive energy and stability versus first Piola-Kirchhoff (nominal) shear stress path under stress control boundary conditions for a cubic crystal at zero absolute temperature. The applied nominal shear stress is defined by a shearing direction and shear plane normal relative to the reference conventional crystal coordinate system. No Results
cohesive-free-energy-cubic-crystal Cohesive free energy of cubic crystal structure at a given temperature under stress-free boundary conditions Cohesive free energy of a cubic crystal at a given temperature under stress-free boundary conditions. No Results
cohesive-free-energy-hexagonal-crystal Cohesive free energy of hexagonal crystal structure at a given temperature under stress-free boundary conditions Cohesive free energy of a hexagonal crystal at a given temperature under stress-free boundary conditions. No Results
cohesive-potential-energy-2d-hexagonal-crystal Cohesive energy of two-dimensional layer hexagonal crystal structure at zero temperature under stress-free boundary conditions Cohesive energy (negative of the potential energy per atom) of a two-dimensional hexagonal crystalline layer at zero temperature under stress-free boundary conditions. Results 28
cohesive-potential-energy-cubic-crystal Cohesive energy of cubic crystal structure at zero temperature under stress-free boundary conditions Cohesive energy (negative of the potential energy per atom) of a cubic crystal at zero temperature under stress-free boundary conditions. Results 3440
cohesive-potential-energy-hexagonal-crystal Cohesive energy of hexagonal crystal structure at zero temperature under stress-free boundary conditions Cohesive energy (negative of the potential energy per atom) of a hexagonal crystal at zero temperature under stress-free boundary conditions. Results 796
configuration-cluster-fixed Static calculation of an isolated cluster of particles (unrelaxed) Energy (and, optionally, forces) of an isolated cluster of particles at zero absolute temperature in a fixed configuration. No Results
configuration-cluster-relaxed Static minimization of an isolated cluster of particles Energy (and, optionally, forces) of an isolated cluster of particles at zero absolute temperature in an unrelaxed configuration and a corresponding relaxed configuration. Results 28854
configuration-nonorthogonal-periodic-3d-cell-fixed-particles-fixed Static calculation of a non-orthogonal periodic cell of particles (cell fixed, particles fixed) Energy (and, optionally, forces and stresses) of a non-orthogonal periodic cell of particles at zero absolute temperature in a fixed configuration. Results 8837
configuration-nonorthogonal-periodic-3d-cell-fixed-particles-relaxed Static minimization of non-orthogonal periodic cell with fixed cell vectors (cell fixed, particles fixed) Energy (and, optionally, forces and stresses) of a non-orthogonal periodic cell of particles at zero absolute temperature in an unrelaxed configuration and a corresponding relaxed configuration. The particle positions are allowed to change in the course of relaxation, but the periodic cell vectors are held fixed. No Results
configuration-nonorthogonal-periodic-3d-cell-relaxed-particles-fixed Static calculation of a non-orthogonal periodic cell of particles (cell relaxed, particles fixed) Energy (and, optionally, forces and stresses) of a non-orthogonal periodic cell of particles at zero absolute temperature in an unrelaxed configuration and a corresponding relaxed configuration. The periodic cell vectors are allowed to change in the course of relaxation, but the fractional particle positions are held fixed. No Results
configuration-nonorthogonal-periodic-3d-cell-relaxed-particles-relaxed Static calculation of a non-orthogonal periodic cell of particles (cell relaxed, particles relaxed) Energy (and, optionally, forces and stresses) of a non-orthogonal periodic cell of particles in an unrelaxed configuration and a corresponding relaxed configuration. Both the periodic cell vectors and the particle positions are allowed to change in the course of relaxation. No Results
configuration-periodic-2d-cell-fixed-particles-fixed Static calculation of a two-dimensional periodic cell of particles (cell fixed, particles fixed) Energy (and, optionally, forces and stresses) of a two-dimensional periodic cell of particles at zero absolute temperature with the cell and particles held fixed. No Results
crystal-structure-npt Equilibrium crystal structure at a given temperature and stress state Equilibrium structure of a crystal at a given temperature and applied stress. The equilibrium structure is expressed as an AFLOW prototype label and its corresponding free parameters representing the average positions of the constituent atoms. Multiple instances of this property with different free parameters may be reported for a given AFLOW prototype label, representing different local stable or unstable equilibria. There is no guarantee that any instance of this property represents the state of minimum Helmholtz free energy of this system, not even when the configuration space is restricted to the specified crystal prototype label. Results 220
dislocation-core-energy-cubic-crystal-npt Dislocation core energy of a cubic crystal at zero temperature and a given stress state The dislocation core energy is a mathematical construct designed to remove the singularity in the stress and strain fields of elasticity theory. The total strain energy is computed relative to the cohesive energy of the ideal crystal, and the core energy is the portion of this energy that is not accounted for by an elastic model. In this property, the dislocation core energy for cubic crystals at zero temperature and a given stress state is reported using three different elastic models: nonsingular, isotropic, and anisotropic. Each of these core energies is computed for a range of dislocation core cutoff radii and is given in units of energy per unit dislocation line length. Results 272
elastic-constants-first-strain-gradient-isothermal-cubic-crystal-npt Isothermal first strain gradient elastic constants for a cubic crystal at its equilibrium lattice spacing The three independent isothermal classical elastic constants c11, c12 and c44, and eleven independent isothermal strain gradient elastic constants d-1-1, d-1-2, d-1-3, d-2-2, d-2-3, d-2-4, d-2-5, d-3-3, d-3-5, d-16-16 and d-16-17, for a cubic crystal at 0 K and zero stress. (The classical and strain gradient elastic constants are the 2nd derivatives of the strain energy density with respect to the Lagrangian strain and the Lagrangian strain gradient respectively.) Results 4
elastic-constants-first-strain-gradient-isothermal-monoatomic-hexagonal-crystal-npt Isothermal first strain gradient elastic constants for a hexagonal crystal at its equilibrium lattice spacing The five independent isothermal classical elastic constants c11, c12, c13, c33, and c55, and twenty two independent isothermal strain gradient elastic constants d-1-1, d-6-6, d-6-7, d-6-8, d-6-9, d-6-10, d-7-7, d-8-9, d-8-10, d-9-9, d-9-10, d-10-10, d-11-11, d-11-12, d-11-13, d-12-12, d-12-13, d-13-13, d-16-16, d-16-17, d-17-17, and d-17-18, for a hexagonal simple lattice at 0 K and zero stress. The orientation of the lattice is such that the e_3 axis is perpendicular to the basal plane, and the e_2 axis passes through a vertex of the hexagon. (The classical and strain gradient elastic constants are the 2nd derivatives of the strain energy density with respect to the Lagrangian strain and the Lagrangian strain gradient respectively.) No Results
elastic-constants-isothermal-cubic-crystal-npt Isothermal elastic constants for a cubic crystal at constant temperature and stress The three independent isothermal elastic constants c11, c12 and c44 for a cubic crystal at a constant given temperature and stress. (The elastic constants are the 2nd derivatives of the strain energy density with respect to strain.) Results 2967
enthalpy-of-mixing-curve-substitutional-binary-cubic-crystal-npt Enthalpy of Mixing versus Concentration for Substitutional Random Binary A-B Cubic Crystal Alloys under NPT Conditions Enthalpy of mixing per atom versus concentration for a random solid solution binary alloy of species A and B at constant pressure and temperature. The enthalpy of mixing per atom is defined as the enthalpy of the binary alloy less the enthalpies of each species in the same crystal structure normalized by the number of atoms. This property is defined for the case where at zero concentration the crystal consists entirely of A atoms, and at concentration one, the crystal is entirely of species B. At each concentration the potential energy of the binary alloy is minimized. No Results
enthalpy-of-mixing-curve-substitutional-binary-cubic-crystal-nvt Enthalpy of Mixing versus Concentration for Substitutional Random Binary A-B Cubic Crystal Alloys under NVT Conditions Enthalpy of mixing per atom versus concentration for a random solid solution binary alloy of species A and B at constant volume and temperature. The enthalpy of mixing per atom is defined as the enthalpy of the binary alloy less the enthalpies of each species in the same crystal structure normalized by the number of atoms. This property is defined for the case where at zero concentration the crystal consists entirely of A atoms, and at concentration one, the crystal is entirely of species B. At each concentration the potential energy of the binary alloy is minimized. No Results
extrinsic-stacking-fault-relaxed-energy-fcc-crystal-npt Relaxed extrinsic stacking fault energy for a monoatomic fcc crystal at a zero temperature and a given pressure The extrinsic stacking fault (ESF) energy for a monoatomic fcc crystal at zero temperature and a specified pressure. The ESF corresponds to an ABC|BA|BC stacking, which can also be understood as a two-layer twin nucleus. Relaxation of the atomic coordinates is performed in the direction perpendicular to the fault plane. Results 315
gamma-surface-relaxed-fcc-crystal-npt The relaxed gamma surface created by rigid slip of a (111) plane on a grid of points defined by [112] and [-110] directions in a monoatomic fcc crystal at zero temperature and a given pressure The relaxed energy-per-area versus all possible slips lying in the (111) lattice plane defines the Gamma surface. Due to periodicity of the crystal lattice, it suffices to sample a grid of points that span a*sqrt(6)/2 and a*sqrt(2)/2 along the [112] and [-110] directions, respectively. This is achieved through a sequence of rigid displacements applied to one part of an fcc crystal relative to another on the (111) plane on a grid defined by the [112] and [-110] directions at zero temperature and a specified pressure. Following each slip displacement, a relaxation of the atomic coordinates is performed in the direction perpendicular to the slip plane to arrive at the energy-per-area. Results 315
grain-boundary-symmetric-tilt-energy-ideal-cubic-crystal Ideal symmetric tilt grain boundary energy for a cubic crystal The unrelaxed energy of a grain boundary for a cubic bi-crystal characterized by a symmetric tilt axis and angle for zero applied loads. No Results
grain-boundary-symmetric-tilt-energy-relaxed-cubic-crystal Relaxed symmetric tilt grain boundary energy for a cubic crystal The relaxed energy of a grain boundary for a cubic bi-crystal characterized by a symmetric tilt axis and angle for zero applied loads. No Results
grain-boundary-symmetric-tilt-energy-relaxed-relation-cubic-crystal Relaxed symmetric tilt grain boundary energy versus tilt angle relation for a cubic crystal The relaxed energy versus tilt angle relation of a grain boundary for a cubic bi-crystal characterized by a symmetric tilt axis and angle for zero applied loads. Results 1327
intrinsic-stacking-fault-relaxed-energy-fcc-crystal-npt Relaxed intrinsic stacking fault energy for a monoatomic fcc crystal at zero temperature and a given pressure The intrinsic stacking fault (ISF) energy for a monoatomic fcc crystal at zero temperature and a specified pressure. The ISF corresponds to a fault of the form ABC|BCA. Relaxation of the atomic coordinates is performed in the direction perpendicular to the fault plane. Results 315
linear-thermal-expansion-coefficient-cubic-crystal-npt Linear thermal expansion coefficient of a cubic crystal structure at given temperature and pressure Linear thermal expansion coefficient of a cubic crystal structure at given temperature and pressure, calculated from (change-in-length)/(original-length)/(change-in-temperature). Results 454
melting-temperature-constant-pressure-cubic-crystal Melting temperature of a cubic crystal structure at a given hydrostatic stress Melting temperature of a cubic crystal structure at a given hydrostatic stress. This is the temperature at which the crystal and liquid are in thermal equilibrium. No Results
monovacancy-formation-energy-monoatomic-cubic-diamond Formation energy of a monovacancy in a monoatomic cubic diamond crystal at zero absolute temperature Unrelaxed and relaxed formation potential energies of a monovacancy in a monoatomic cubic diamond crystal with stress-free boundary conditions at zero absolute temperature. No Results
monovacancy-neutral-formation-free-energy-crystal-npt Formation free energy of a neutral monovacancy in a general crystal at finite temperature and stress Gibbs free energy of formation of a neutral monovacancy in a (possibly multispecies) infinite host crystal lattice at a specific temperature and stress state relative to a given infinite monoatomic reference lattice ('reservoir') at a possibly different temperature and stress state. No Results
monovacancy-neutral-migration-energy-crystal-npt Migration energy of neutral monovacancy at zero temperature and given stress state The energy barrier that must be overcome to transition (at zero temperature and a given stress state) from the initial configuration, a relaxed infinite host crystal lattice with a neutral monovacancy (associated with a missing atom of type 'host-missing-atom-start'), to the final relaxed configuration, where the monovacancy has moved to one of the nearest neighbor lattice sites (which is originally occupied by an atom of type 'host-missing-atom-end'). Results 621
monovacancy-neutral-relaxation-volume-crystal-npt Volume change from relaxation of neighboring atoms around a neutral vacant atom site in a crystal at zero temperature and a given stress state Volume change from relaxation of neighboring atoms around a neutral vacant atom site at a given stress state in a (possibly multispecies) infinite host crystal lattice at zero temperature. Results 655
monovacancy-neutral-relaxed-formation-potential-energy-crystal-npt Relaxed formation potential energy of a neutral monovacancy in a crystal at zero temperature and a given stress state Relaxed potential energy of formation of a neutral monovacancy in a (possibly multispecies) infinite host crystal lattice at zero temperature relative to a given infinite monoatomic reference lattice ('reservoir') at zero temperature. Results 1276
monovacancy-neutral-unrelaxed-formation-potential-energy-crystal-npt Unrelaxed formation potential energy of a neutral monovacancy in a crystal at zero temperature and a given stress state Unrelaxed potential energy of formation of a neutral monovacancy in a (possibly multispecies) infinite host crystal lattice at zero temperature relative to a given infinite monoatomic reference lattice ('reservoir') at zero temperature. Results 655
phonon-dispersion-dos-cubic-crystal-npt Phonon dispersion density of states for a cubic crystal Density of states of the phonon dispersion energies of a cubic crystal at given temperature and pressure. Results 329
phonon-dispersion-relation-cubic-crystal-npt Single wave direction phonon dispersion relation for a cubic crystal Phonon dispersion relation for a cubic crystal at a given temperature and pressure. The dispersion relation is provided for a single wave direction. It consists of multiple branches (three for a monoatomic crystal, more for crystals with more than one basis atom per unit cell). Results 329
shear-stress-path-cubic-crystal Shear strain and stability versus first Piola-Kirchhoff shear stress path of a cubic crystal Shear strain and stability versus first Piola-Kirchhoff (nominal) shear stress path under stress control boundary conditions for a cubic crystal at zero absolute temperature. The applied nominal shear stress is defined by a shearing direction and shear plane normal relative to the reference conventional crystal coordinate system. No Results
stacking-fault-relaxed-energy-curve-fcc-crystal-npt Relaxed stacking energy per unit area curve for layer-by-layer rigid slip on {111}<112> in a monoatomic fcc crystal at zero temperature and a specified pressure The energy-per-area versus slip curve associated with a deformation twinning process in which a sequence of faults is generated by sequentially rigidly displacing one part of a monoatomic fcc crystal relative to another on a {111} plane along a <112> direction at zero temperature and a specified pressure. The following sequence of structures is traversed by the curve: ideal crystal -> intrinsic stacking fault -> two-layer twin nucleus. Each energy is computed after performing relaxation of the atomic coordinates in the direction perpendicular to the fault plane. Results 315
structure-2d-hexagonal-crystal-npt Equilibrium two-dimensional layer hexagonal crystal structure at a given temperature and stress state Conventional lattice parameter and basis atoms of a two-dimensional hexagonal crystalline layer at a given temperature and stress state. Results 28
structure-cubic-crystal-npt Equilibrium cubic crystal structure at a given temperature and hydrostatic stress Conventional lattice parameter and basis atom positions of a cubic crystal at a given temperature and hydrostatic pressure. Results 3423
structure-hexagonal-crystal-npt Equilibrium hexagonal crystal structure at a given temperature and stress state Conventional lattice parameters of a hexagonal crystal at a given temperature and stress state. Results 796
structure-monoclinic-crystal-npt Equilibrium monoclinic crystal structure at a given temperature and stress state Conventional lattice parameters and basis atom positions of a monoclinic crystal at a given temperature and stress state. No Results
structure-orthorhombic-crystal-npt Equilibrium orthorhombic crystal structure at a given temperature and stress state Conventional lattice parameters and basis atom positions of a orthorhombic crystal at a given temperature and stress state. No Results
structure-rhombohedral-crystal-npt Equilibrium rhombohedral crystal structure at a given temperature and stress state Conventional lattice parameters of a rhombohedral crystal at a given temperature and stress state. No Results
structure-tetragonal-crystal-npt Equilibrium tetragonal crystal structure at a given temperature and stress state Conventional lattice parameters and basis atom positions of a tetragonal crystal at a given temperature and stress state. No Results
structure-triclinic-crystal-npt Equilibrium triclinic crystal structure at a given temperature and stress state Conventional lattice parameters and basis atom positions of a triclinic crystal at a given temperature and stress state. No Results
surface-energy-broken-bond-fit-cubic-bravais-crystal-npt Surface energy broken bond fit model Surface energy fit obtained by calculating the number of broken bonds created by cleaving a crystal at a given hydrostatic stress and temperature. These are the prefactors associated with each term in the model. Results 530
surface-energy-cubic-crystal-npt Surface energy for a cubic crystal A surface (free) energy of a cubic monoatomic crystal at a specified hydrostatic stress and temperature. If computed, this corresponds to the 'relaxed' surface energy found by performing an energy minimization. At zero temperature, the calculation is for the potential energy as opposed to the free energy. Results 530
surface-energy-ideal-cubic-crystal Ideal surface energy for a cubic crystal The surface energy of a cubic crystal for a surface obtained from the ideal crystal structure by cleaving along a specified plane, possibly with specified step structure or adsorbates. Results 530
unstable-stacking-fault-relaxed-energy-fcc-crystal-npt Relaxed unstable stacking energy for a monoatomic fcc crystal at zero temperature and a given pressure The relaxed unstable stacking energy (USE) for a monoatomic fcc crystal at zero temperature and a specified pressure. The USE corresponds to the energy barrier for rigidly slipping one-half of an infinite crystal relative to the other along a <112> direction (fcc partial dislocation direction). Relaxation of the atomic positions is performed perpendicular to the fault plane. Results 315
unstable-twinning-fault-relaxed-energy-fcc-crystal-npt Relaxed unstable twinning energy for a monoatomic fcc crystal at zero temperature and a given pressure The relaxed unstable twinning energy (UTE) for a monoatomic fcc crystal at a zero temperature and a specified pressure. The UTE corresponds to the energy barrier for rigidly slipping one part of an infinite crystal on a {111} plane adjacent to a preexisting intrinsic stacking fault relative to the other part along a <112> direction (fcc partial dislocation direction). Relaxation of the atomic coordinates is performed perpendicular to the fault plane. Results 315
verification-check Universal verification check property Verification checks are designed to explore basic model characteristics and conformance to the KIM API standard. Results from verification checks are reported in the standardized form defined in this property definition. No Results