Purpose of postahc.x:
- Read the electron-phonon quantities calculated by ph.x with the
electron_phonon='ahc' option.
- Calculate the phonon-induced electron self-energy in the full matrix form
at a given temperature.
Structure of the input data:
========================================================================
&INPUT
...specs of namelist variables...
/
'pwscf'
Prepended to input/output filenames; must be the same
used in the calculation of unperturbed system.
value of the ESPRESSO_TMPDIR environment variable if set;
current directory ('./') otherwise
Directory containing input, output, and scratch files;
must be the same as specified in the calculation of
the unperturbed system.
REQUIRED
Directory where the binary files are located.
.false.
If .true., assume that the q points are on the irreducible grid. In this case,
the data in [ahc_dir] must have been actually generated from a calculation
on an irreducible q grid.
Off-diagonal self-energies cannot be computed if use_irr_q = .true.
REQUIRED
Number of bands for which the electron self-energy is to be computed. Must be
identical to ahc_nbnd of the ph.x run with electron_phonon='ahc'.
0
Number of bands to exclude when computing the self-energy. Must be identical to
ahc_nbndskip of the ph.x run with electron_phonon='ahc'.
REQUIRED
File containing the normalized phonon displacements written by matdyn.x.
REQUIRED
Magnitude of the small imaginary component included to smooth the energy
denominators, in eV.
REQUIRED
Temperature in Kelvins at which the electron self-energy is calculated.
REQUIRED
Fermi energy of the electrons in eV.
REQUIRED
Mass for each atom type in atomic mass unit.
-1.d8
Lower bound of active AHC window for the lower Fan term in eV.
1.d8
Upper bound of active AHC window for the lower Fan term in eV.
.false.
If .true., skip calculation of the upper Fan self-energy. Also, truncate the
Debye-Waller self-energy to include only the low-energy band contribution.
(Corresponds to the second term (lower Fan + lower DW) of Eq. (G1-revised) of
J.-M. Lihm and C.-H. Park, PRX 12, 039901(E) (2022).)
If .false., calculate the contribution of both the high-energy and low-energy
bands. In this case, ahc_upfan_iq#.bin files must be present in [ahc_dir].
.false.
If .true., skip calculation of the Debye-Waller self-energy.
If .false., ahc_dw.bin file must be present in [ahc_dir].
.false.
If .true., use the adiabatic approximation when computing the Fan self-energy
by ignoring the phonon frequency in the denominator. This approximation is known
to be inaccurate and even divergent in some materials (S. Poncé et al., J. Chem.
Phys. 143, 102813 (2015)). Therefore, this keyword should be used only for
experimental or debugging purposes.