Parameters for calculating ZT

Parameters here are for calculating thermoelectric properties, including the thermoelectric figure of merit ZT and the related properties Seebeck coefficient S, electrical conductivity sigma, and thermal conductivity kappa with both lattice and electronic contributions.

calculation.ZT.systemObjectFiles

keyword: calculation.ZT.systemObjectFiles

possible values: cells of file names

default value: no default value

description: It is supposed that the calculations for the electronic Hamiltonian (SCF) and the phononic Hamiltonian (Hessian) have already been completed seperatly. This parameter gives in order the file names of the calculated cNanodcal objects for the electronic and the phononic calculations, or the calculated transmissions for the electron and the phonon.

an example:

calculation.ZT.systemObjectFiles = ...
{'./electron/NanodcalObject.mat', ...
'./phonon/NanodcalObject.mat'}

calculation.ZT.whatDirection

keyword: calculation.ZT.whatDirection

possible values: 1, 2, or 3

default value: 3

description: The transmission direction of the system, which need to simulate. It is necessary to choose one and only one of the three central cell vectors as the lead direction (i.e. transmission direction); the transverse plane is spanned by the other two directions.

an example:

calculation.ZT.whatDirection = 3

calculation.ZT.temperature

keyword: calculation.ZT.temperature

possible values: n x 1 double array with n an integer

default value: 300

description: The electronic and phononic temperature of the system, in the unit of K.

Note: the Boltzmann constant k = 8.617342e-05(eV/K) / 27.2113834(eV/Hartree) = 3.1668151e-06 (Hartree/K).

an example:

calculation.ZT.temperature = [50:50:500]

calculation.ZT.chemicalPotentialEnergy

keyword: calculation.ZT.chemicalPotentialEnergy

possible values: n x 1 double array with proper energy unit such as ‘eV’, ‘meV’, ‘Ryd’, ‘Ryd.’, ‘Rydberg’, ‘au’, ‘a.u.’, ‘atomic unit’, ‘Hartree’, where ‘au’ ‘a.u.’, and ‘atomic unit’ are for Hartree, ‘Ryd’, ‘Ryd.’ for Rydberg.

default value: 0

description: The thermoelectric figure of merit ZT and other related properties will be calculated respectively when the chemical potential energy is set to those input values.

Note that the chemical potential energy is measured from the calculated Fermi energy and is in the unit of meV.

an example:

calculation.ZT.chemicalPotentialEnergy = [0:10:100] meV

calculation.ZT.kSpaceGridNumber

keyword: calculation.ZT.kSpaceGridNumber

possible values: 3 x 1 integer array

default value: the value of calculation.k_spacegrids.number which was used in the electronic Hamiltonian calculation.

description: The number of small k-space grids in each direction, which are used in the electronic k-space integration.

an example:

calculation.ZT.kSpaceGridNumber = [10 10 10]'

calculation.ZT.qSpaceGridNumber

keyword: calculation.ZT.qSpaceGridNumber

possible values: 3 x 1 integer array

default value: the value of calculation.k_spacegrids.number which was used in the original electronic Hamiltonian calculation.

description: The number of small q-space grids in each direction, which are used in the phononic q-space integration.

an example:

calculation.ZT.qSpaceGridNumber = [10 10 10]'

calculation.ZT.energyInterval

keyword: calculation.ZT.energyInterval

possible values: a double number with proper energy unit such as ‘eV’, ‘meV’, ‘Ryd’, ‘Ryd.’, ‘Rydberg’, ‘au’, ‘a.u.’, ‘atomic unit’, ‘Hartree’, where ‘au’ ‘a.u.’, and ‘atomic unit’ are for Hartree, ‘Ryd’, ‘Ryd.’ for Rydberg.

default value: 0.3 (kT)

description: Energy interval used in the electronic and phononic energy-space integration.

an example:

calculation.ZT.energyInterval = 2 meV

calculation.ZT.plot

keyword: calculation.ZT.plot

possible values: true or false

default value: false

description: If true, a plot will be given after the calculation.

an example:

calculation.ZT.plot = true