# MaterialSpecifications¶

class MaterialSpecifications(pristine_configuration, supercell_repetitions=None, formation_energy_calculator=None, relaxation_calculator=None, phonon_calculator=None, amorphization_calculator=None, amorphous_density=None, atomic_chemical_potentials=None, dielectric_constant=None, bulk_modulus=None, assumed_formation_entropy=None, assumed_transition_prefactor=None, first_nearest_neighbor=None, second_nearest_neighbor=None, color=None, sentaurus_material_name=None, optimize_geometry_parameters=None, symmetry_tolerance=None)

A class defining a bulk material to use in an SMW simulation. The class encapsulates the structure of the pristine unit cell and all the technical options needed to perform the calculations.

Parameters: pristine_configuration (BulkConfiguration) – The reference bulk unit cell configuration to be used to generate the supercell configuration. supercell_repetitions (sequence (size 3) of int) – The number of repetitions of the reference bulk unit cell along the (a, b, c) directions. Default: (1, 1, 1) formation_energy_calculator (Calculator) – The calculator used for calculating the formation energy of the defect charge states. Note that the calculator is taken as a reference corresponding to the bulk unit cell given in pristine_configuration; the density_mesh_cutoff and k_point_sampling parameters of the NumericalAccuracyParameters of the calculator will be scaled consistently with the supercell size. Default: The calculator given in relaxation_calculator. At least one of the two calculators must be provided. relaxation_calculator (Calculator) – The calculator used for relaxing the atomic coordinates of the defect supercells. Note that the calculator is taken as a reference corresponding to the bulk unit cell given in pristine_configuration; the density_mesh_cutoff and k_point_sampling parameters of the NumericalAccuracyParameters of the calculator will be scaled consistently with the supercell size. Default: The calculator given in formation_energy_calculator. At least one of the two calculators must be provided. phonon_calculator – The calculator used for performing phonon calculations. Note that the calculator is taken as a reference corresponding to the bulk unit cell given in pristine_configuration; the density_mesh_cutoff and k_point_sampling parameters of the NumericalAccuracyParameters of the calculator will be scaled consistently with the supercell size. Default: The calculator given in relaxation_calculator. amorphization_calculator (Calculator) – The calculator used for producing amorphous structures. This should typically be a force field calculator since the amorphization procedure requires many force evaluations. Default: None amorphous_density (PhysicalQuantity of type mass per volume) – The target density of this material when producing amorphous structures. If not value is given, then the density will be the same as the pristine configuration. Default: None atomic_chemical_potentials (list of AtomicChemicalPotential | None) – The atomic chemical potential for each element of interest. See the documentation of AtomicChemicalPotential for details on how to define the atomic chemical potential for a species, and how the default values are calculated. Default: None; all necessary atomic chemical potentials calculated using the default configurations. dielectric_constant (float) – The dielectric constant of the pristine material. Only needed to calculate the finite-size electrostatic energy correction terms. Default: 1.0 bulk_modulus (PhysicalQuantity of type pressure) – The bulk modulus of the pristine material. Only needed to calculate the finite-size elastic energy correction term. Default: 100.0 * GPa assumed_formation_entropy (PhysicalQuantity of type entropy) – The assumed formation entropy of all defects calculated for this material. Setting this parameter will disable all phonon contributions to the defects. Default: Phonon contributions will be calculated. assumed_transition_prefactor (PhysicalQuantity of type frequency) – The assumed prefactor for all transition paths calculated for this material. Setting this parameter will disable the prefactor calculation from the vibrational frequencies at the minima and saddle point for all transition paths. Default: The prefactors will be calculated from the vibrational frequencies at the minima and saddle point. first_nearest_neighbor (PhysicalQuantity of type length) – The distance for first nearest neighbors in the material Default: Distance automatically calculated. second_nearest_neighbor (PhysicalQuantity of type length) – The distance for second nearest neighbors in the material Default: Distance automatically calculated. color (Valid color in hexadecimal format as str) – A representative color for this material. Default: “#FFFFFF” sentaurus_material_name (str) – The material name for Sentaurus tools. A typical use is when writing parameters for other Sentaurus (Process, Device) tools. This parameter is only needed when providing parameters for other tools. Otherwise it can be left empty. But if a name is not provided, an exception/error will be raised when used by functions providing parameters for other Sentaurus tools. Default: None optimize_geometry_parameters (OptimizeGeometryParameters) – The parameters to use for optimizing the geometry. Note that constraints, pre_step_hook andpost_step_hook must be left unset. Default: OptimizeGeometryParameters() symmetry_tolerance (PhysicalQuantity of type length.) – The tolerance to be used when determining the symmetries. Default: 0.01 * Angstrom
amorphizationCalculator()
Returns: The reference calculator used for performing amorphization calculations. Calculator | None
amorphousDensity()
Returns: The target density of this material when producing amorphous structures. PhysicalQuantity of type mass per volume
assumedFormationEntropy()
Returns: The assumed formation entropy of all defects calculated for this material. If None, the phonon contributions are calculated explicitly. PhysicalQuantity of type entropy | None
assumedTransitionPrefactor()
Returns: The assumed prefactor for all transition paths calculated for this material. If None, the prefactors are calculated explicitly from the vibrational frequencies at the minima and saddle point. PhysicalQuantity of type frequency | None
atomicChemicalPotentials()
Returns: The list of atomic chemical potentials for each element. list of AtomicChemicalPotential
bulkModulus()
Returns: The bulk modulus of the pristine material. PhysicalQuantity of type pressure
color()
Returns: The color of the material. str
description()
Returns: The description of the material. str
dielectricConstant()
Returns: The dielectric constant of the pristine material. float
firstNearestNeighbor()
Returns: The first nearest neighbor distance associated to this system. PhysicalQuantity of type length
formationEnergyCalculator()
Returns: The reference calculator used for calculating the formation energy of the defect charge states. Calculator
name()
Returns: The name of the material, mostly used for displaying purposes. This name might not be unique for different specifications. Do not use for indexing purposes. str
optimizeGeometryParameters()
Returns: Parameters required to optimize the geometry. OptimizeGeometryParameters
phononCalculator()
Returns: The reference calculator used for performing phonon calculations. Calculator
pristineConfiguration()
Returns: The reference bulk unit cell configuration used to generate the supercell configuration. BulkConfiguration
relaxationCalculator()
Returns: The reference calculator used for relaxing the atomic coordinates of the defect supercells. Calculator
secondNearestNeighbor()
Returns: The second nearest neighbor distance associated to this system. PhysicalQuantity of type length
sentaurusMaterialName()
Returns: The name to be used for this material in Sentarus tools str
setDescription(description)
Parameters: description (str) – The description of the material.
supercellRepetitions()
Returns: The number of repetitions of the reference bulk unit cell along the (a, b, c) directions. tuple (size 3) of int
symmetryTolerance`()
Returns: The tolerance to be used when determining the symmetries. PhysicalQuantity of type length.