ELPH_SELFEN_DELTA
ELPH_SELFEN_DELTA = [real array]
Default: ELPH_SELFEN_DELTA = 0.01
Description: Complex imaginary shift to use when computing the self-energy due to electron-phonon coupling.
If the value is set to 0.0 then the tetrahedron method is used to perform the Brillouin zone integrals and evaluate only the imaginary part of the electron self-energy. This is the recommended option for transport calculations.
For bandgap renormalization since one is mainly interested in the real part of the self-energy due to electron-phonon coupling, a small finite value should be used and a dense k point mesh used.
If more than one value is specified, the number of self-energy accumulators is increased such that one exists for each value in this array. It is possible to compute the self-energy using the tetrahedron method and a finite complex shift in the same run.