calculatePhononRetardedGreenFunction

calculatePhononRetardedGreenFunction(device_configuration, dynamical_matrix=None, energy=PhysicalQuantity(0.0, eV), kpoint=None, eta=PhysicalQuantity(1e-06, Hartree), self_energy_calculator=None)

Calculate the Phonon Retarded Green’s Function.

Parameters:

• device_configuration (DeviceConfiguration) – The configuration to use for the calculation.

• dynamical_matrix (DynamicalMatrix) – The dynamical matrix to use in the calculation.

• energy (PhysicalQuantity of type energy) – Absolute energy for the calculation
  Default: 0.0 * eV

• kpoint (tuple of floats) – The kpoint as three floats representing fractional reciprocal space coordinates.
  Default: The Gamma point (0.0, 0.0, 0.0)

• eta (PhysicalQuantity of type energy) – Complex energy for electrode transform matrices, imaginary part.
  Default: 1.0e-6 * Hartree

• self_energy_calculator (RecursionSelfEnergy | DirectSelfEnergy | KrylovSelfEnergy | SparseRecursionSelfEnergy) – The self energy evaluation strategy to use.
  Default: A default RecursionSelfEnergy instance.

Returns:

The Phonons Green’s Function as an array

Return type:

PhysicalQuantity of type energy squared

Usage Examples

Evaluate on a DeviceConfiguration:

phonon_green_function = calculatePhononRetardedGreenFunction(device_configuration)

Notes

• The calculator assigned to the device must be density matrix-based for this function to perform successfully.