mirror of https://gitlab.com/QEF/q-e.git
141 lines
4.1 KiB
Fortran
141 lines
4.1 KiB
Fortran
!
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! Copyright (C) 2001-2013 Quantum ESPRESSO group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!-----------------------------------------------------------------------
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SUBROUTINE do_phonon(auxdyn)
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!-----------------------------------------------------------------------
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!
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! ... This is the main driver of the phonon code.
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! ... It assumes that the preparatory stuff has been already done.
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! ... When the code calls this routine it has already read input
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! ... decided which irreducible representations have to be calculated
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! ... and it has set the variables that decide which work this routine
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! ... will do. The parallel stuff has been already setup by the calling
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! ... codes. This routine makes the two loops over
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! ... the q points and the irreps and does only the calculations
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! ... that have been decided by the driver routine.
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! ... At a generic q, if necessary it recalculates the band structure
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! ... calling pwscf again.
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! ... Then it can calculate the response to an atomic displacement,
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! ... the dynamical matrix at that q, and the electron-phonon
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! ... interaction at that q. At q=0 it can calculate the linear response
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! ... to an electric field perturbation and hence the dielectric
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! ... constant, the Born effective charges and the polarizability
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! ... at imaginary frequencies.
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! ... At q=0, from the second order response to an electric field,
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! ... it can calculate also the electro-optic and the raman tensors.
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!
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USE disp, ONLY : nqs
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USE control_ph, ONLY : epsil, trans, qplot, only_init, &
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only_wfc, rec_code, where_rec
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USE el_phon, ONLY : elph, elph_mat, elph_simple
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!
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! YAMBO >
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USE YAMBO, ONLY : elph_yambo
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! YAMBO <
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!
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USE elph_tetra_mod, ONLY : elph_tetra, elph_tetra_lambda, elph_tetra_gamma
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USE elph_scdft_mod, ONLY : elph_scdft
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IMPLICIT NONE
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!
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CHARACTER (LEN=256), INTENT(IN) :: auxdyn
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INTEGER :: iq
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LOGICAL :: do_band, do_iq, setup_pw
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!
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DO iq = 1, nqs
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!
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CALL prepare_q(auxdyn, do_band, do_iq, setup_pw, iq)
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!
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! If this q is not done in this run, cycle
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!
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IF (.NOT.do_iq) CYCLE
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!
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! If necessary the bands are recalculated
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!
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IF (setup_pw) CALL run_nscf(do_band, iq)
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!
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! If only_wfc=.TRUE. the code computes only the wavefunctions
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!
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IF (only_wfc) THEN
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where_rec='only_wfc'
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rec_code=-1000
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GOTO 100
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ENDIF
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!
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! Initialize the quantities which do not depend on
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! the linear response of the system
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!
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CALL initialize_ph()
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!
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! electric field perturbation
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!
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IF (epsil) CALL phescf()
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!
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! IF only_init is .true. the code computes only the
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! initialization parts.
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!
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IF (only_init) THEN
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where_rec='only_init'
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rec_code=-1000
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GOTO 100
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ENDIF
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!
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! phonon perturbation
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!
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IF ( trans ) THEN
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!
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CALL phqscf()
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CALL dynmatrix_new(iq)
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!
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END IF
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!
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CALL rotate_dvscf_star(iq)
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!
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! electron-phonon interaction
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!
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IF ( elph ) THEN
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!
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IF ( .NOT. trans ) THEN
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!
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CALL dvanqq()
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IF ( elph_mat ) THEN
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CALL ep_matrix_element_wannier()
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ELSE
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CALL elphon()
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END IF
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!
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END IF
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!
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IF ( elph_mat ) THEN
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CALL elphsum_wannier(iq)
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ELSEIF( elph_simple ) THEN
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CALL elphsum_simple()
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ELSEIF( elph_yambo ) THEN
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CALL elph_yambo_eval_and_IO()
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ELSEIF(elph_tetra == 1) THEN
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CALL elph_tetra_lambda()
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ELSEIF(elph_tetra == 2) THEN
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CALL elph_tetra_gamma()
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ELSEIF(elph_tetra == 3) THEN
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CALL elph_scdft()
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ELSE
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!CALL elphsum()
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CALL elphsum2()
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END IF
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!
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END IF
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!
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! ... cleanup of the variables for the next q point
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!
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100 CALL clean_pw_ph(iq)
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!
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END DO
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END SUBROUTINE do_phonon
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