| Property Definition (short name)
A common way to refer to the Property Definition. Note there may be multiple Property Definitions with the same short name, to fully distinguish between Property Definitions the full Tag URI must be used (the Property Definition ID).
| binding-energy-crystal |
|---|---|
| Property Definition ID
The full Property Definition identifier using the Tag URI scheme.
| tag:staff@noreply.openkim.org,2023-02-21:property/binding-energy-crystal |
| Title
A brief one-sentence description of this Property Definition.
| Equilibrium crystal structure and binding potential energy at zero temperature and applied stress |
| Description
A description about this Property Definition.
| 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. |
| Contributor
The user or organization who initially contributed this Property Definition.
| ilia |
| Maintainer
The user or organization who currently maintains this Property Definition.
| ilia |
| Creation date
The date the Property Definition was "minted", based on its Tag URI.
| 2023-02-21 |
| Content on GitHub
The following content may be available on GitHub: Property Definition (an EDN file containing the Property Definition Keys listed below); Physics Validator (a script provided by the user for validating that an instance of the Property is physically valid); Property Documentation Wiki (the contents of the Wiki displayed at the bottom of this page).
|
Property Definition Physics Validator Property Documentation Wiki |
| type | float |
|---|---|
| has-unit | true |
| extent | [] |
| required | true |
| description | The equilibrium 'a' lattice constant of the crystal structure as defined by the AFLOW standard. Relative values of other lattice parameters (if present) are given in the 'parameter-values' key. |
| type | float |
|---|---|
| has-unit | true |
| extent | [] |
| required | true |
| description | Binding potential energy per atom of the crystal defined as follows: \Delta \bar{V}_{atom} = ( V(A_{N_A}B_{N_B}...) - [N_A V_{isolated}(A) + N_B V_{isolated}(B) + ...] )/(N_A + N_B ...), where \Delta \bar{V}_{atom} is the binding energy per atom, V(A_{N_A}B_{N_B}...) is the energy of (any) unit cell, V_{isolated}(X) is the energy of an isolated particle of species X, and N_X is the number of atoms of species X in the (same) unit cell. |
| type | float |
|---|---|
| has-unit | true |
| extent | [] |
| required | true |
| description | This variable has the same definition as 'binding-potential-energy-per-atom' except that the energy is normalized per chemical formula instead of per atom, i.e. \Delta \bar{V}_{formula} = \Delta \bar{V}_{atom} N_{formula}, where N_{formula} is the number of atoms in the reduced stoichiometric formula, i.e. the sum of indices in the first section of the prototype-label. |
| type | string |
|---|---|
| has-unit | false |
| extent | [] |
| required | true |
| description | Prototype label (not including an enumeration suffix) as defined by the AFLOW standard (e.g. 'A_tI4_141_a') for the structure. It is expected that the alphabetically lowest of all equivalent labels is chosen. |
| type | string |
|---|---|
| has-unit | false |
| extent | [":"] |
| required | true |
| description | Element symbols corresponding to the atom types in the stoichiometric formula which appears at the start of the prototype label (e.g. ['Mo','S'] for the AB2 stoichiometric formula, means that the 'A' atom is 'Mo' and the 'B' atom is 'S' for the MoS_2 structure). |
| type | file |
|---|---|
| has-unit | false |
| extent | [] |
| required | false |
| description | A file containing the atomic configuration including information such as the species, x,y,z coordinates of each particle, and periodicity data. |
| type | string |
|---|---|
| has-unit | false |
| extent | [] |
| required | false |
| description | The AFLOW library prototype, if any, matching the equilibrium structure. Prototypes in the AFLOW library are associated with common short names used by the materials community. The library prototype includes an integer enumeration suffix defined by the AFLOW standard when there are multiple parameter values associated with the structure (e.g. 'A_tI4_141_a-001' for 'betaSn'). Because these prototype labels are named according to their original material's conventional chemical formula, they may differ from the 'prototype-label' key, which is expected to be standardized to have the alphabetically lowest possible of all equivalent labels. |
| type | string |
|---|---|
| has-unit | false |
| extent | [":"] |
| required | false |
| description | Names of the parameters other than 'a', if present, corresponding to this AFLOW prototype. These can include lattice parameters from the set {'b/a','c/a','alpha','beta','gamma'} (for the conventional crystal structure defined by lattice parameters a, b, and c and angles alpha, beta, gamma), and coordinates of Wyckoff positions that have a degree of variability labeled as 'x*', 'y*' and 'z*' where the asterisk represents an integer as defined by the AFLOW standard. |
| type | float |
|---|---|
| has-unit | false |
| extent | [":"] |
| required | false |
| description | Equilibrium values for the parameters listed in 'parameter-names'. Note that all parameters are dimensionless. |
| type | string |
|---|---|
| has-unit | false |
| extent | [":"] |
| required | false |
| description | Commonly used name associated with the 'library-prototype-label' key according to the AFLOW prototype library (e.g. 'Face-Centered Cubic' or 'Molybdenite'). |