EPWpy.QE.PH_util#

Functions

get_dielectric_matrix(ph_file)

get_gkk(ph_file)

get_polarization_vec(dynmat_file, atoms, natoms)

Reads dynmat.axsf file to return polarization vectors

get_qpoints(ph_file)

Classes

PHProperties(file[, energy_range, version])

A class for parsing and analyzing phonon (PH) calculation properties.
class EPWpy.QE.PH_util.PHProperties(file, energy_range=None, version=7.4)[source]#

Bases: object

A class for parsing and analyzing phonon (PH) calculation properties.

This class provides access to various physical quantities derived from Quantum ESPRESSO (QE) ph.x output files, such as dielectric constants, Fermi level, band structures, and lattice vectors. It serves as a post-processing utility to extract, store, and manipulate phonon-related data.

Parameters:

  • file (str) -- Path to the phonon output file generated by QE (ph.out).

  • energy_range (float, optional) -- Energy window (in eV) around the Fermi level for evaluating band-related quantities. Defaults to None.

eps#

Static dielectric constant of the system.

Type:

float

nbnd_energy#

Number of bands within the specified energy range.

Type:

int

lattice_vec#

Lattice vectors extracted from the associated PW calculation.

Type:

ndarray

fermi_level#

Fermi energy or the highest occupied band energy (in eV).

Type:

float

atomic_positions#

Atomic positions in Cartesian or fractional coordinates.

Type:

ndarray

band_scf#

Self-consistent field (SCF) band structure data array.

Type:

ndarray

Examples

>>> ph = PHProperties(file='Si.ph.out', energy_range=5.0)
>>> print(ph.file)
'Si.ph.out'
>>> print(ph.energy_range)
5.0
property dynmat#

Returns the dynamical matrix

property eps_ph#

Returns high-frequency dielectric matrix from DFPT

property gkk#

Returns the electron–phonon coupling matrix g(ibnd, jbnd, imode, ik, iq) extracted from a Quantum ESPRESSO ph.x output file.

The matrix has dimensions:

(nbnd_i, nbnd_j, nmodes, nkpoints, nqpoints)

where:

  • ibnd, jbnd: band indices

  • imode: phonon mode index

  • ik, iq: k-point and q-point indices

Returns:

5D array of electron–phonon coupling strengths in units consistent with the QE output.

Return type:

np.ndarray

ph_properties()[source]#

Returns various phonon related outputs

plot_pl_vector(mode)[source]#

performs a quiver plot of pl vectors

property polarization_vector#

Compute and return the polarization vectors from the dynamical matrix file.

This property reads the dynmat.axsf file generated by dynmat.x and extracts the atomic displacement (polarization) vectors corresponding to phonon modes at the Γ-point or other q-points, depending on the underlying calculation.

Returns:

A 3D NumPy array of shape (nmode, natoms, 6) containing the polarization vectors and atomic coordinates for each phonon mode. Returns None if no polarization data are found.

Return type:

numpy.ndarray or None

Notes

Each entry in the last dimension (6 columns) corresponds typically to: [x, y, z, dx, dy, dz], where (x, y, z) are atomic positions and (dx, dy, dz) are displacement components for a given mode.

property qpoints#

Returns q-points for Ph calculation

EPWpy.QE.PH_util.get_dielectric_matrix(ph_file)[source]#
EPWpy.QE.PH_util.get_gkk(ph_file)[source]#
EPWpy.QE.PH_util.get_polarization_vec(dynmat_file, atoms, natoms)[source]#

Reads dynmat.axsf file to return polarization vectors

EPWpy.QE.PH_util.get_qpoints(ph_file)[source]#