calculatePhononGreenFunctionComponent(device_configuration, dynamical_matrix=None, energy=PhysicalQuantity(0.0, eV), kpoint=None, contribution=<class 'NL.ComputerScienceUtilities.NLFlag._NLFlag.Left'>, eta=PhysicalQuantity(1e-06, Hartree), self_energy_calculator=None)

Calculate the Phonon Green’s Function Component, \(G \Gamma G^\dagger\).

  • 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)
  • contribution (Left | Right) – Which electrode to consider for the evaluation.
    Default: Left
  • 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.

Phonon Green’s Function Component as an array

Return type:

PhysicalQuantity of type energy squared

Usage Examples

Evaluate on a DeviceConfiguration:

phonon_green_function_component = calculatePhononGreenFunctionComponent(device_configuration)


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