httk property definitionsProperty definitions using the OPTIMADE property definition format, hosted by httk
This page documents an OPTIMADE Property Definition. See https://schemas.optimade.org/ for more information.
ID: https://schemas.httk.org/defs/v0.1/properties/mechanics/piezoelectric_tensor
Definition name: piezoelectric_tensor
Property name: Piezoelectric tensor
Description: The piezoelectric stress tensor e of the referenced structure in Voigt notation, in coulomb per square metre.
Type: list
Implementation requirements:
- Support: OPTIONAL support in implementations, i.e., MAY be null.
Requirements/Conventions:
dim_spatial of lists over _httk_dim_voigt.elastic_tensor, so that the strain-induced polarization is P_i = sum_J e_{iJ} epsilon_J and e_{iJ} equals the tensor component e_{ijk} = dP_i / d(epsilon_jk) for J = (jk).lattice_vectors and cartesian_site_positions.A null value means the quantity is not available or not recorded.
Examples:
JSON definition:
{
"$id": "https://schemas.httk.org/defs/v0.1/properties/mechanics/piezoelectric_tensor",
"$schema": "https://schemas.optimade.org/meta/v1.3/optimade/property_definition.json",
"title": "Piezoelectric tensor",
"x-optimade-type": "list",
"x-optimade-definition": {
"kind": "property",
"version": "0.1.0",
"format": "1.3",
"name": "piezoelectric_tensor",
"label": "piezoelectric_tensor_mechanics_httk"
},
"x-optimade-unit": "C*m^-2",
"x-optimade-unit-definitions": [
{
"$id": "https://schemas.optimade.org/defs/v1.2/units/si/general/coulomb",
"title": "coulomb",
"symbol": "C",
"display-symbol": "C",
"description": "A unit for electric charge equal to s\u00b7A using the current, or one of the historical, definitions of the SI units.\n\n\"The coulomb is the amount of electricity transported in one second by a current of one ampere.\" [9th CGPM meeting in 1946]\n\nThe coulomb was defined at the 9th CGPM Meeting in 1946, included in SI at the 11th CGPM meeting in 1960, resolution 12, implicitly redefined via the redefinitions of the second at the 13th CGPM Meeting in 1967, resolution 1; the metre at the 17th CGPM meeting (1983), resolution 1; and the kilogram at the 26th CGPM Meeting (2018), resolution 1.\n\nThis is a generalized definition taken to reference the current, or one of the historical, SI unit definitions.\nThis definition is intended for situations when it is not possible to be more precise, e.g., in contexts where data have been collected that uses different historical SI definitions.",
"compatibility": [
"https://schemas.optimade.org/defs/v1.2/units/si/1960/named/coulomb",
"https://schemas.optimade.org/defs/v1.2/units/si/1967/named/coulomb",
"https://schemas.optimade.org/defs/v1.2/units/si/1983/named/coulomb",
"https://schemas.optimade.org/defs/v1.2/units/si/2019/named/coulomb"
],
"resources": [
{
"relation": "Definition at the 9th CGPM meeting (1948)",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/9-1948"
},
{
"relation": "Definition and establishment of the SI unit system at the 11th CGPM meeting (1960), resolution 12.",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/11-1960/resolution-12"
},
{
"relation": "Redefinition of the second in the 13th CGPM Meeting (1967), resolution 1",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/13-1967/resolution-1"
},
{
"relation": "Redefinition of the kilogram in the 26th CGPM Meeting (2018), resolution 1",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/26-2018/resolution-1"
},
{
"relation": "Wikipedia article describing the unit",
"resource-id": "https://en.wikipedia.org/wiki/Coulomb"
}
],
"defining-relation": {
"base-units": [
{
"symbol": "s",
"id": "https://schemas.optimade.org/defs/v1.2/units/si/general/second"
},
{
"symbol": "A",
"id": "https://schemas.optimade.org/defs/v1.2/units/si/general/ampere"
}
],
"base-units-expression": "A*s"
},
"x-optimade-definition": {
"label": "coulomb_si_general",
"kind": "unit",
"format": "1.2",
"version": "1.2.0",
"name": "coulomb"
}
},
{
"$id": "https://schemas.optimade.org/defs/v1.2/units/si/general/metre",
"title": "metre",
"symbol": "m",
"display-symbol": "m",
"alternate-symbols": [
"metre",
"meter"
],
"description": "The metre, or meter, is a unit of length using the current, or one of the historical, definitions of the SI units.\n\nThe current definition in its most recent phrasing at the 26th CGPM Meeting in 2018, resolution 1 is: \"The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum \\(c\\) to be 299792458 when expressed in the unit m\u22c5s\u207b\u00b9, where the second is defined in terms of the caesium frequency \\(\\Delta \\nu_\\textrm{Cs}\\).\"\n\nThis is a rephrasing of a definition at the 17th CGPM Meeting (1983), resolution 1: \"The metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second.\" [17th CGPM Meeting (1983), resolution 1].\n\nThe prior definition at the 11th CGPM meeting (1960), resolution 6 was: \"The metre is the length equal to 1650763.73 wavelengths in vacuum of the radiation corresponding to the transition between the levels 2p\u2081\u2080 and 5d\u2085 of the krypton 86 atom.\"\n\nThis is a generalized definition taken to reference the current, or one of the historical, SI unit definitions.\nThis definition is intended for situations when it is not possible to be more precise, e.g., in contexts where data have been collected that uses different historical SI definitions.",
"compatibility": [
"https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre",
"https://schemas.optimade.org/defs/v1.2/units/si/1983/base/metre"
],
"resources": [
{
"relation": "Definition at the 17th CGPM meeting (1983), resolution 1",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/17-1983/resolution-1"
},
{
"relation": "Definition at the 11th CGPM meeting (1960), resolution 6.",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/11-1960/resolution-6"
},
{
"relation": "Wikipedia article describing the unit",
"resource-id": "https://en.wikipedia.org/wiki/Metre"
}
],
"x-optimade-definition": {
"label": "metre_si_general",
"kind": "unit",
"format": "1.2",
"version": "1.2.0",
"name": "metre"
}
}
],
"x-optimade-requirements": {
"support": "may",
"sortable": false,
"query-support": "none"
},
"x-optimade-dimensions": {
"names": [
"dim_spatial"
],
"sizes": [
3
]
},
"type": [
"array",
"null"
],
"items": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_voigt"
],
"sizes": [
6
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "float",
"x-optimade-unit": "C*m^-2",
"type": [
"number"
]
}
},
"description": "The piezoelectric stress tensor e of the referenced structure in Voigt notation, in coulomb per square metre.\n\n**Requirements/Conventions**:\n\n- The value is a 3x6 matrix: a list over `dim_spatial` of lists over `_httk_dim_voigt`.\n- The element e_{iJ} = dP_i / d(epsilon_J) at zero macroscopic electric field is the change of the macroscopic polarization P along the Cartesian direction i (the row) with the strain component J (the column), where J is the Voigt strain index in the order [xx, yy, zz, yz, xz, xy].\n The Voigt strain has engineering shear components (epsilon_yz in Voigt form is gamma_yz = 2 epsilon_yz, likewise for xz and xy), as for `elastic_tensor`, so that the strain-induced polarization is P_i = sum_J e_{iJ} epsilon_J and e_{iJ} equals the tensor component e_{ijk} = dP_i / d(epsilon_jk) for J = (jk).\n- The directions refer to the Cartesian frame of the referenced structure (the entry the record is a product of), that is the frame of its `lattice_vectors` and `cartesian_site_positions`.\n- The tensor is the total relaxed-ion response: the sum of the clamped-ion (electronic) contribution and the ionic contribution from the internal relaxation of the atoms under strain.\n\nA null value means the quantity is not available or not recorded."
}