ElectrodeParameters

	Core NanoLanguage elements
calculateTransmissionSpectrum	energyContourIntegralParameters

Name

ElectrodeParameters — Defines calculation specific parameters for electrodes in a two-probe system.

Synopsis

Namespace: ATK.TwoProbe

Object ElectrodeParameters(
electron_density_parameters,
eigenstate_occupation_parameters,
iteration_mixing_parameters,
iteration_control_parameters,
brillouin_zone_integration_parameters
)

Description

The ElectrodeParameters class is used to represent parameters that control certain aspects of the calculation of the electrodes in a two-probe system. The returned object is used as an input parameter to a TwoProbeMethod, thereby defining how the electrodes should be calculated. To define the geometry of the electrode, use PeriodicAtomConfiguration.

This class is very similar to the method objects KohnShamMethod (for bulk and molecule systems) and TwoProbeMethod (two-probe), but with some noticeable differences:

First of all, it is not possible to run an electrode calculation separately; it must always be part of a two-probe calculation. Therefore, this class is not called a method.

Second, there are certain parameters that appear to be missing, such as basis_set_parameters, etc. These are inherited from the corresponding parameters for the complete two-probe system at the time of the actual calculation. For this reason, it is not possible to use a different basis set in the electrode compared to the scattering region, since that would make it impossible to match the density matrix between the scattering region and the electrode.

List of arguments

electron_density_parameters

A dictionary of parameters such as the mesh cut-off and, if applicable, initial spin of the atoms.

Default: Parameters corresponding to electronDensityParameters() supplied with no arguments.

eigenstate_occupation_parameters

A dictionary of parameters such as the Fermi temperature of the electrode.

Default: Parameters corresponding to eigenstateOccupationParameters() supplied with no arguments.

iteration_mixing_parameters

A dictionary of parameters that control the mixing in the self-consistent iteration.

Default: Parameters corresponding to iterationMixingParameters() supplied with no arguments.

iteration_control_parameters

A dictionary of parameters that determine the convergence criteria for the self-consistent iteration.

Default: Parameters corresponding to iterationControlParameters() supplied with no arguments.

brillouin_zone_integration_parameters

Defines the k-point mesh in the Brillouin zone of the electrode cell. This has no default value and must be specified using the function brillouinZoneIntegrationParameters().

Default: None

Usage examples

Define electrode method:

electrode_bz=brillouinZoneIntegrationParameters((1, 1, 500))
electrode_parms=ElectrodeParameters(
    brillouin_zone_integration_parameters=electrode_bz
    )

Notes

The brillouin_zone_integration_parameters must always be specified since no default value is assigned to this variable. Omitting the other parameters leads to a setting corresponding to their respective default values as described in the respective help sections.

The k-point sampling refers to the electrode cell, which is defined using a PeriodicAtomConfiguration. For electrodes in two-probes, the two first vectors must be perpendicular to the third. The two first parameters of the brillouinZoneIntegrationParameters(), which correspond to the 2D Brillouin zone perpendicular to the transport direction, will subsequently be used for the transverse k-point sampling for the two-probe calculation.

Further examples


calculateTransmissionSpectrum		energyContourIntegralParameters