mirror of https://gitlab.com/QEF/q-e.git
1253 lines
40 KiB
Fortran
1253 lines
40 KiB
Fortran
!
|
|
! Copyright (C) 2001-2013 Quantum ESPRESSO group
|
|
! This file is distributed under the terms of the
|
|
! GNU General Public License. See the file `License'
|
|
! in the root directory of the present distribution,
|
|
! or http://www.gnu.org/copyleft/gpl.txt .
|
|
!
|
|
!
|
|
!-----------------------------------------------------------------------
|
|
SUBROUTINE elphon()
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! Electron-phonon calculation from data saved in fildvscf
|
|
!
|
|
USE kinds, ONLY : DP
|
|
USE constants, ONLY : amu_ry
|
|
USE cell_base, ONLY : celldm, omega, ibrav, at, bg
|
|
USE ions_base, ONLY : nat, ntyp => nsp, ityp, tau, amass
|
|
USE gvecs, ONLY: doublegrid
|
|
USE fft_base, ONLY : dfftp, dffts
|
|
USE noncollin_module, ONLY : nspin_mag, noncolin, m_loc
|
|
USE lsda_mod, ONLY : nspin
|
|
USE uspp, ONLY: okvan
|
|
USE paw_variables, ONLY : okpaw
|
|
USE el_phon, ONLY : done_elph
|
|
USE dynmat, ONLY : dyn, w2
|
|
USE modes, ONLY : npert, nirr, u
|
|
USE uspp_param, ONLY : nhm
|
|
USE control_ph, ONLY : trans, xmldyn
|
|
USE output, ONLY : fildyn,fildvscf
|
|
USE io_dyn_mat, ONLY : read_dyn_mat_param, read_dyn_mat_header, &
|
|
read_dyn_mat, read_dyn_mat_tail
|
|
USE units_ph, ONLY : iudyn, lrdrho, iudvscf, iuint3paw, lint3paw
|
|
USE dfile_star, ONLY : dvscf_star
|
|
USE mp_bands, ONLY : intra_bgrp_comm, me_bgrp, root_bgrp
|
|
USE mp, ONLY : mp_bcast
|
|
USE io_global, ONLY: stdout
|
|
|
|
USE lrus, ONLY : int3, int3_nc, int3_paw
|
|
USE qpoint, ONLY : xq
|
|
!
|
|
IMPLICIT NONE
|
|
!
|
|
INTEGER :: irr, imode0, ipert, is, npe
|
|
! counter on the representations
|
|
! counter on the modes
|
|
! the change of Vscf due to perturbations
|
|
COMPLEX(DP), POINTER :: dvscfin(:,:,:), dvscfins (:,:,:)
|
|
|
|
INTEGER :: ntyp_, nat_, ibrav_, nspin_mag_, mu, nu, na, nb, nta, ntb, nqs_
|
|
REAL(DP) :: celldm_(6)
|
|
CHARACTER(LEN=3) :: atm(ntyp)
|
|
|
|
CALL start_clock ('elphon')
|
|
|
|
if(dvscf_star%basis.eq.'cartesian') then
|
|
write(stdout,*) 'Setting patterns to identity'
|
|
u=CMPLX(0.d0,0.d0)
|
|
do irr=1,3*nat
|
|
u(irr,irr)=CMPLX(1.d0,0.d0)
|
|
enddo
|
|
endif
|
|
!
|
|
! read Delta Vscf and calculate electron-phonon coefficients
|
|
!
|
|
imode0 = 0
|
|
WRITE (6, '(5x,a)') "Reading dVscf from file "//trim(fildvscf)
|
|
DO irr = 1, nirr
|
|
npe=npert(irr)
|
|
ALLOCATE (dvscfin (dfftp%nnr, nspin_mag , npe) )
|
|
IF (okvan) THEN
|
|
ALLOCATE (int3 ( nhm, nhm, nat, nspin_mag, npe))
|
|
IF (okpaw) ALLOCATE (int3_paw (nhm, nhm, nat, nspin_mag, npe))
|
|
IF (noncolin) ALLOCATE(int3_nc( nhm, nhm, nat, nspin, npe))
|
|
ENDIF
|
|
DO ipert = 1, npe
|
|
CALL davcio_drho ( dvscfin(1,1,ipert), lrdrho, iudvscf, &
|
|
imode0 + ipert, -1 )
|
|
IF (okpaw .AND. me_bgrp==0) &
|
|
CALL davcio( int3_paw(:,:,:,:,ipert), lint3paw, &
|
|
iuint3paw, imode0 + ipert, - 1 )
|
|
END DO
|
|
IF (okpaw) CALL mp_bcast(int3_paw, root_bgrp, intra_bgrp_comm)
|
|
IF (doublegrid) THEN
|
|
ALLOCATE (dvscfins (dffts%nnr, nspin_mag , npert(irr)) )
|
|
DO is = 1, nspin_mag
|
|
DO ipert = 1, npe
|
|
CALL cinterpolate (dvscfin(1,is,ipert),dvscfins(1,is,ipert),-1)
|
|
ENDDO
|
|
ENDDO
|
|
ELSE
|
|
dvscfins => dvscfin
|
|
ENDIF
|
|
CALL newdq (dvscfin, npert(irr))
|
|
CALL elphel (irr, npert (irr), imode0, dvscfins)
|
|
!
|
|
imode0 = imode0 + npe
|
|
IF (doublegrid) DEALLOCATE (dvscfins)
|
|
DEALLOCATE (dvscfin)
|
|
IF (okvan) THEN
|
|
DEALLOCATE (int3)
|
|
IF (okpaw) DEALLOCATE (int3_paw)
|
|
IF (noncolin) DEALLOCATE(int3_nc)
|
|
ENDIF
|
|
ENDDO
|
|
!
|
|
! now read the eigenvalues and eigenvectors of the dynamical matrix
|
|
! calculated in a previous run
|
|
!
|
|
IF (.NOT.trans) THEN
|
|
IF (.NOT. xmldyn) THEN
|
|
WRITE (6, '(5x,a)') "Reading dynamics matrix from file "//trim(fildyn)
|
|
CALL readmat (iudyn, ibrav, celldm, nat, ntyp, &
|
|
ityp, omega, amass, tau, xq, w2, dyn)
|
|
ELSE
|
|
CALL read_dyn_mat_param(fildyn, ntyp_, nat_)
|
|
IF ( ntyp_ /= ntyp .OR. nat_ /= nat ) &
|
|
CALL errore('elphon','uncorrect nat or ntyp',1)
|
|
|
|
CALL read_dyn_mat_header(ntyp, nat, ibrav_, nspin_mag_, &
|
|
celldm_, at, bg, omega, atm, amass, tau, ityp, &
|
|
m_loc, nqs_)
|
|
|
|
IF (ibrav_.NE.ibrav .OR. ABS ( celldm_ (1) - celldm (1) ) > 1.0d-5 &
|
|
.OR. (nspin_mag_ /= nspin_mag ) ) CALL errore ('elphon', &
|
|
'inconsistent data', 1)
|
|
|
|
CALL read_dyn_mat(nat,1,xq,dyn)
|
|
!
|
|
! Diagonalize the dynamical matrix
|
|
!
|
|
DO mu = 1, 3*nat
|
|
na = (mu - 1) / 3 + 1
|
|
nta = ityp (na)
|
|
DO nu = 1, 3*nat
|
|
nb = (nu - 1) / 3 + 1
|
|
ntb = ityp (nb)
|
|
dyn (mu, nu) = dyn (mu, nu) / &
|
|
sqrt (amass (nta)*amass (ntb)) / amu_ry
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
CALL cdiagh (3 * nat, dyn, 3 * nat, w2, dyn)
|
|
!
|
|
! divide by sqrt(mass) to get displacements
|
|
!
|
|
DO nu = 1, 3 * nat
|
|
DO mu = 1, 3 * nat
|
|
na = (mu - 1) / 3 + 1
|
|
dyn (mu, nu) = dyn (mu, nu) / SQRT ( amu_ry * amass (ityp (na) ) )
|
|
ENDDO
|
|
ENDDO
|
|
|
|
CALL read_dyn_mat_tail(nat)
|
|
ENDIF
|
|
ENDIF
|
|
!
|
|
CALL stop_clock ('elphon')
|
|
RETURN
|
|
END SUBROUTINE elphon
|
|
!
|
|
!-----------------------------------------------------------------------
|
|
SUBROUTINE readmat (iudyn, ibrav, celldm, nat, ntyp, ityp, omega, &
|
|
amass, tau, q, w2, dyn)
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
USE kinds, ONLY : DP
|
|
USE constants, ONLY : amu_ry
|
|
IMPLICIT NONE
|
|
! Input
|
|
INTEGER :: iudyn, ibrav, nat, ntyp, ityp (nat)
|
|
REAL(DP) :: celldm (6), amass (ntyp), tau (3, nat), q (3), &
|
|
omega
|
|
! output
|
|
REAL(DP) :: w2 (3 * nat)
|
|
COMPLEX(DP) :: dyn (3 * nat, 3 * nat)
|
|
! local (control variables)
|
|
INTEGER :: ntyp_, nat_, ibrav_, ityp_
|
|
REAL(DP) :: celldm_ (6), amass_, tau_ (3), q_ (3)
|
|
! local
|
|
REAL(DP) :: dynr (2, 3, nat, 3, nat)
|
|
CHARACTER(len=80) :: line
|
|
CHARACTER(len=3) :: atm
|
|
INTEGER :: nt, na, nb, naa, nbb, nu, mu, i, j
|
|
!
|
|
!
|
|
REWIND (iudyn)
|
|
READ (iudyn, '(a)') line
|
|
READ (iudyn, '(a)') line
|
|
READ (iudyn, * ) ntyp_, nat_, ibrav_, celldm_
|
|
IF ( ntyp.NE.ntyp_ .OR. nat.NE.nat_ .OR.ibrav_.NE.ibrav .OR. &
|
|
ABS ( celldm_ (1) - celldm (1) ) > 1.0d-5) &
|
|
CALL errore ('readmat', 'inconsistent data', 1)
|
|
DO nt = 1, ntyp
|
|
READ (iudyn, * ) i, atm, amass_
|
|
IF ( nt.NE.i .OR. ABS (amass_ - amu_ry*amass (nt) ) > 1.0d-5) &
|
|
CALL errore ( 'readmat', 'inconsistent data', 1 + nt)
|
|
ENDDO
|
|
DO na = 1, nat
|
|
READ (iudyn, * ) i, ityp_, tau_
|
|
IF (na.NE.i.OR.ityp_.NE.ityp (na) ) CALL errore ('readmat', &
|
|
'inconsistent data', 10 + na)
|
|
ENDDO
|
|
READ (iudyn, '(a)') line
|
|
READ (iudyn, '(a)') line
|
|
READ (iudyn, '(a)') line
|
|
READ (iudyn, '(a)') line
|
|
READ (line (11:80), * ) (q_ (i), i = 1, 3)
|
|
READ (iudyn, '(a)') line
|
|
DO na = 1, nat
|
|
DO nb = 1, nat
|
|
READ (iudyn, * ) naa, nbb
|
|
IF (na.NE.naa.OR.nb.NE.nbb) CALL errore ('readmat', 'error reading &
|
|
&file', nb)
|
|
READ (iudyn, * ) ( (dynr (1, i, na, j, nb), dynr (2, i, na, j, nb) &
|
|
, j = 1, 3), i = 1, 3)
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
! divide the dynamical matrix by the (input) masses (in amu)
|
|
!
|
|
DO nb = 1, nat
|
|
DO j = 1, 3
|
|
DO na = 1, nat
|
|
DO i = 1, 3
|
|
dynr (1, i, na, j, nb) = dynr (1, i, na, j, nb) / SQRT (amass ( &
|
|
ityp (na) ) * amass (ityp (nb) ) ) / amu_ry
|
|
dynr (2, i, na, j, nb) = dynr (2, i, na, j, nb) / SQRT (amass ( &
|
|
ityp (na) ) * amass (ityp (nb) ) ) / amu_ry
|
|
ENDDO
|
|
ENDDO
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
! solve the eigenvalue problem.
|
|
! NOTA BENE: eigenvectors are overwritten on dyn
|
|
!
|
|
CALL cdiagh (3 * nat, dynr, 3 * nat, w2, dyn)
|
|
!
|
|
! divide by sqrt(mass) to get displacements
|
|
!
|
|
DO nu = 1, 3 * nat
|
|
DO mu = 1, 3 * nat
|
|
na = (mu - 1) / 3 + 1
|
|
dyn (mu, nu) = dyn (mu, nu) / SQRT ( amu_ry * amass (ityp (na) ) )
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
!
|
|
RETURN
|
|
END SUBROUTINE readmat
|
|
!
|
|
!-----------------------------------------------------------------------
|
|
SUBROUTINE elphel (irr, npe, imode0, dvscfins)
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! Calculation of the electron-phonon matrix elements el_ph_mat
|
|
! <\psi(k+q)|dV_{SCF}/du^q_{i a}|\psi(k)>
|
|
! Original routine written by Francesco Mauri
|
|
!
|
|
USE kinds, ONLY : DP
|
|
USE fft_base, ONLY : dffts
|
|
USE fft_parallel, ONLY : tg_cgather
|
|
USE wavefunctions_module, ONLY: evc
|
|
USE io_files, ONLY: iunigk
|
|
USE buffers, ONLY : get_buffer
|
|
USE klist, ONLY: xk
|
|
USE lsda_mod, ONLY: lsda, current_spin, isk
|
|
USE noncollin_module, ONLY : noncolin, npol, nspin_mag
|
|
USE wvfct, ONLY: nbnd, npw, npwx, igk
|
|
USE buffers, ONLY : get_buffer
|
|
USE uspp, ONLY : vkb
|
|
USE el_phon, ONLY : el_ph_mat, el_ph_mat_rec, el_ph_mat_rec_col, &
|
|
comp_elph, done_elph
|
|
USE modes, ONLY : u
|
|
USE units_ph, ONLY : iubar, lrbar, lrwfc, iuwfc
|
|
USE control_ph, ONLY : trans, current_iq
|
|
USE ph_restart, ONLY : ph_writefile
|
|
USE spin_orb, ONLY : domag
|
|
USE mp_bands, ONLY: intra_bgrp_comm, ntask_groups
|
|
USE mp_pools, ONLY: npool
|
|
USE mp, ONLY: mp_sum
|
|
|
|
USE eqv, ONLY : dvpsi, evq
|
|
USE qpoint, ONLY : igkq, npwq, nksq, ikks, ikqs, nksqtot
|
|
USE control_lr, ONLY : lgamma
|
|
|
|
IMPLICIT NONE
|
|
!
|
|
INTEGER, INTENT(IN) :: irr, npe, imode0
|
|
COMPLEX(DP), INTENT(IN) :: dvscfins (dffts%nnr, nspin_mag, npe)
|
|
! LOCAL variables
|
|
INTEGER :: nrec, ik, ikk, ikq, ipert, mode, ibnd, jbnd, ir, ig, &
|
|
ipol, ios, ierr
|
|
COMPLEX(DP) , ALLOCATABLE :: aux1 (:,:), elphmat (:,:,:), tg_dv(:,:), &
|
|
tg_psic(:,:), aux2(:,:)
|
|
INTEGER :: v_siz, incr
|
|
COMPLEX(DP), EXTERNAL :: zdotc
|
|
!
|
|
IF (.NOT. comp_elph(irr) .OR. done_elph(irr)) RETURN
|
|
IF ( ntask_groups > 1 ) dffts%have_task_groups=.TRUE.
|
|
|
|
ALLOCATE (aux1 (dffts%nnr, npol))
|
|
ALLOCATE (elphmat ( nbnd , nbnd , npe))
|
|
ALLOCATE( el_ph_mat_rec (nbnd,nbnd,nksq,npe) )
|
|
el_ph_mat_rec=(0.0_DP,0.0_DP)
|
|
ALLOCATE (aux2(npwx*npol, nbnd))
|
|
incr=1
|
|
IF ( dffts%have_task_groups ) THEN
|
|
!
|
|
v_siz = dffts%tg_nnr * dffts%nogrp
|
|
ALLOCATE( tg_dv ( v_siz, nspin_mag ) )
|
|
ALLOCATE( tg_psic( v_siz, npol ) )
|
|
incr = dffts%nogrp
|
|
!
|
|
ENDIF
|
|
!
|
|
! Start the loops over the k-points
|
|
!
|
|
IF (nksq.GT.1) REWIND (unit = iunigk)
|
|
DO ik = 1, nksq
|
|
IF (nksq.GT.1) THEN
|
|
READ (iunigk, err = 100, iostat = ios) npw, igk
|
|
100 CALL errore ('elphel', 'reading igk', ABS (ios) )
|
|
ENDIF
|
|
!
|
|
! ik = counter of k-points with vector k
|
|
! ikk= index of k-point with vector k
|
|
! ikq= index of k-point with vector k+q
|
|
! k and k+q are alternated if q!=0, are the same if q=0
|
|
!
|
|
IF (lgamma) npwq = npw
|
|
ikk = ikks(ik)
|
|
ikq = ikqs(ik)
|
|
IF (lsda) current_spin = isk (ikk)
|
|
IF (.NOT.lgamma.AND.nksq.GT.1) THEN
|
|
READ (iunigk, err = 200, iostat = ios) npwq, igkq
|
|
200 CALL errore ('elphel', 'reading igkq', ABS (ios) )
|
|
ENDIF
|
|
!
|
|
CALL init_us_2 (npwq, igkq, xk (1, ikq), vkb)
|
|
!
|
|
! read unperturbed wavefuctions psi(k) and psi(k+q)
|
|
!
|
|
IF (nksq.GT.1) THEN
|
|
IF (lgamma) THEN
|
|
CALL get_buffer(evc, lrwfc, iuwfc, ikk)
|
|
ELSE
|
|
CALL get_buffer (evc, lrwfc, iuwfc, ikk)
|
|
CALL get_buffer (evq, lrwfc, iuwfc, ikq)
|
|
ENDIF
|
|
ENDIF
|
|
!
|
|
DO ipert = 1, npe
|
|
nrec = (ipert - 1) * nksq + ik
|
|
!
|
|
! dvbare_q*psi_kpoint is read from file (if available) or recalculated
|
|
!
|
|
IF (trans) THEN
|
|
CALL get_buffer (dvpsi, lrbar, iubar, nrec)
|
|
ELSE
|
|
mode = imode0 + ipert
|
|
! TODO : .false. or .true. ???
|
|
CALL dvqpsi_us (ik, u (1, mode), .FALSE. )
|
|
ENDIF
|
|
!
|
|
! calculate dvscf_q*psi_k
|
|
!
|
|
IF ( ntask_groups > 1 ) dffts%have_task_groups=.TRUE.
|
|
IF ( dffts%have_task_groups ) THEN
|
|
IF (noncolin) THEN
|
|
CALL tg_cgather( dffts, dvscfins(:,1,ipert), tg_dv(:,1))
|
|
IF (domag) THEN
|
|
DO ipol=2,4
|
|
CALL tg_cgather( dffts, dvscfins(:,ipol,ipert), &
|
|
tg_dv(:,ipol))
|
|
ENDDO
|
|
ENDIF
|
|
ELSE
|
|
CALL tg_cgather( dffts, dvscfins(:,current_spin,ipert), &
|
|
tg_dv(:,1))
|
|
ENDIF
|
|
ENDIF
|
|
aux2=(0.0_DP,0.0_DP)
|
|
DO ibnd = 1, nbnd, incr
|
|
IF ( dffts%have_task_groups ) THEN
|
|
CALL cft_wave_tg (evc, tg_psic, 1, v_siz, ibnd, nbnd )
|
|
CALL apply_dpot(v_siz, tg_psic, tg_dv, 1)
|
|
CALL cft_wave_tg (aux2, tg_psic, -1, v_siz, ibnd, nbnd)
|
|
ELSE
|
|
CALL cft_wave (evc(1, ibnd), aux1, +1)
|
|
CALL apply_dpot(dffts%nnr, aux1, dvscfins(1,1,ipert), current_spin)
|
|
CALL cft_wave (aux2(1, ibnd), aux1, -1)
|
|
ENDIF
|
|
ENDDO
|
|
dvpsi=dvpsi+aux2
|
|
dffts%have_task_groups=.FALSE.
|
|
|
|
CALL adddvscf (ipert, ik)
|
|
!
|
|
! calculate elphmat(j,i)=<psi_{k+q,j}|dvscf_q*psi_{k,i}> for this pertur
|
|
!
|
|
DO ibnd =1, nbnd
|
|
DO jbnd = 1, nbnd
|
|
elphmat (jbnd, ibnd, ipert) = zdotc (npwq, evq (1, jbnd), 1, &
|
|
dvpsi (1, ibnd), 1)
|
|
IF (noncolin) &
|
|
elphmat (jbnd, ibnd, ipert) = elphmat (jbnd, ibnd, ipert)+ &
|
|
zdotc (npwq, evq(npwx+1,jbnd),1,dvpsi(npwx+1,ibnd), 1)
|
|
ENDDO
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
CALL mp_sum (elphmat, intra_bgrp_comm)
|
|
!
|
|
! save all e-ph matrix elements into el_ph_mat
|
|
!
|
|
DO ipert = 1, npe
|
|
DO jbnd = 1, nbnd
|
|
DO ibnd = 1, nbnd
|
|
el_ph_mat (ibnd, jbnd, ik, ipert + imode0) = elphmat (ibnd, jbnd, ipert)
|
|
el_ph_mat_rec (ibnd, jbnd, ik, ipert ) = elphmat (ibnd, jbnd, ipert)
|
|
ENDDO
|
|
ENDDO
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
done_elph(irr)=.TRUE.
|
|
IF (npool>1) THEN
|
|
ALLOCATE(el_ph_mat_rec_col(nbnd,nbnd,nksqtot,npe))
|
|
CALL el_ph_collect(npe,el_ph_mat_rec,el_ph_mat_rec_col,nksqtot,nksq)
|
|
ELSE
|
|
el_ph_mat_rec_col => el_ph_mat_rec
|
|
ENDIF
|
|
CALL ph_writefile('el_phon',current_iq,irr,ierr)
|
|
IF (npool > 1) DEALLOCATE(el_ph_mat_rec_col)
|
|
DEALLOCATE(el_ph_mat_rec)
|
|
!
|
|
DEALLOCATE (elphmat)
|
|
DEALLOCATE (aux1)
|
|
DEALLOCATE (aux2)
|
|
IF ( ntask_groups > 1) dffts%have_task_groups=.TRUE.
|
|
IF ( dffts%have_task_groups ) THEN
|
|
DEALLOCATE( tg_dv )
|
|
DEALLOCATE( tg_psic )
|
|
ENDIF
|
|
dffts%have_task_groups=.FALSE.
|
|
!
|
|
RETURN
|
|
END SUBROUTINE elphel
|
|
!
|
|
!-----------------------------------------------------------------------
|
|
SUBROUTINE elphsum ( )
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! Sum over BZ of the electron-phonon matrix elements el_ph_mat
|
|
! Original routine written by Francesco Mauri, modified by PG
|
|
! New version by Malgorzata Wierzbowska
|
|
!
|
|
USE kinds, ONLY : DP
|
|
USE constants, ONLY : pi, rytoev, ry_to_cmm1, ry_to_ghz, degspin
|
|
USE ions_base, ONLY : nat, ityp, tau
|
|
USE cell_base, ONLY : at, bg
|
|
USE lsda_mod, ONLY: isk, nspin
|
|
USE klist, ONLY: nks, nkstot, xk, wk, nelec
|
|
USE start_k, ONLY: nk1, nk2, nk3
|
|
USE symm_base, ONLY: s, irt, nsym, invs
|
|
USE noncollin_module, ONLY: nspin_lsda, nspin_mag
|
|
USE wvfct, ONLY: nbnd, et
|
|
USE parameters, ONLY : npk
|
|
USE el_phon, ONLY : el_ph_mat, done_elph, el_ph_nsigma, el_ph_ngauss, &
|
|
el_ph_sigma
|
|
USE modes, ONLY : u, nirr
|
|
USE dynmat, ONLY : dyn, w2
|
|
USE io_global, ONLY : stdout, ionode, ionode_id
|
|
USE xml_io_base, ONLY : create_directory
|
|
USE mp_pools, ONLY : my_pool_id, npool, kunit
|
|
USE mp_images, ONLY : intra_image_comm
|
|
USE mp, ONLY : mp_bcast
|
|
USE control_ph, ONLY : tmp_dir_phq, xmldyn, current_iq
|
|
USE save_ph, ONLY : tmp_dir_save
|
|
USE io_files, ONLY : prefix, tmp_dir, seqopn
|
|
|
|
USE lr_symm_base, ONLY : minus_q, nsymq, rtau
|
|
USE qpoint, ONLY : xq, nksq
|
|
USE control_lr, ONLY : lgamma
|
|
!
|
|
IMPLICIT NONE
|
|
! epsw = 20 cm^-1, in Ry
|
|
REAL(DP), PARAMETER :: epsw = 20.d0 / ry_to_cmm1
|
|
REAL(DP), PARAMETER :: eps = 1.0d-6
|
|
!
|
|
INTEGER :: iuna2Fsave = 40
|
|
!
|
|
REAL(DP), allocatable :: gam(:,:), lamb(:,:)
|
|
!
|
|
! Quantities ending with "fit" are relative to the "dense" grid
|
|
!
|
|
REAL(DP), allocatable :: xkfit(:,:)
|
|
REAL(DP), allocatable, target :: etfit(:,:), wkfit(:)
|
|
INTEGER :: nksfit, nk1fit, nk2fit, nk3fit, nkfit, nksfit_real
|
|
INTEGER, allocatable :: eqkfit(:), eqqfit(:), sfit(:)
|
|
!
|
|
integer :: nq, isq (48), imq
|
|
! nq : degeneracy of the star of q
|
|
! isq: index of q in the star of a given sym.op.
|
|
! imq: index of -q in the star of q (0 if not present)
|
|
real(DP) :: sxq (3, 48)
|
|
! list of vectors in the star of q
|
|
!
|
|
! workspace used for symmetrisation
|
|
!
|
|
COMPLEX(DP), allocatable :: g1(:,:,:), g2(:,:,:), g0(:,:), gf(:,:,:)
|
|
COMPLEX(DP), allocatable :: point(:), noint(:), ctemp(:)
|
|
COMPLEX(DP) :: dyn22(3*nat,3*nat)
|
|
!
|
|
INTEGER :: ik, ikk, ikq, isig, ibnd, jbnd, ipert, jpert, nu, mu, &
|
|
vu, ngauss1, nsig, iuelph, ios, i,k,j, ii, jj
|
|
INTEGER :: nkBZ, nti, ntj, ntk, nkr, itemp1, itemp2, nn, &
|
|
qx,qy,qz,iq,jq,kq
|
|
INTEGER, ALLOCATABLE :: eqBZ(:), sBZ(:)
|
|
REAL(DP) :: weight, wqa, w0g1, w0g2, degauss1, dosef, &
|
|
ef1, lambda, gamma
|
|
REAL(DP), ALLOCATABLE :: deg(:), effit(:), dosfit(:)
|
|
REAL(DP) :: etk, etq
|
|
REAL(DP), EXTERNAL :: dos_ef, efermig, w0gauss
|
|
character(len=80) :: name
|
|
LOGICAL :: exst, xmldyn_save
|
|
!
|
|
COMPLEX(DP) :: el_ph_sum (3*nat,3*nat)
|
|
|
|
COMPLEX(DP), POINTER :: el_ph_mat_collect(:,:,:,:)
|
|
REAL(DP), ALLOCATABLE :: xk_collect(:,:)
|
|
REAL(DP), POINTER :: wkfit_dist(:), etfit_dist(:,:)
|
|
INTEGER :: nksfit_dist, rest, kunit_save
|
|
INTEGER :: nks_real, ispin, nksqtot, irr
|
|
CHARACTER(LEN=256) :: elph_dir
|
|
CHARACTER(LEN=6) :: int_to_char
|
|
!
|
|
!
|
|
!
|
|
! If the electron phonon matrix elements have not been calculated for
|
|
! all representations this routine exit
|
|
!
|
|
DO irr=1,nirr
|
|
IF (.NOT.done_elph(irr)) RETURN
|
|
ENDDO
|
|
elph_dir='elph_dir/'
|
|
IF (ionode) INQUIRE(file=TRIM(elph_dir), EXIST=exst)
|
|
CALL mp_bcast(exst, ionode_id, intra_image_comm)
|
|
IF (.NOT.exst) CALL create_directory( elph_dir )
|
|
WRITE (6, '(5x,"electron-phonon interaction ..."/)')
|
|
ngauss1 = 0
|
|
nsig =el_ph_nsigma
|
|
|
|
ALLOCATE(xk_collect(3,nkstot))
|
|
|
|
ALLOCATE(deg(nsig))
|
|
ALLOCATE(effit(nsig))
|
|
ALLOCATE(dosfit(nsig))
|
|
|
|
IF (npool==1) THEN
|
|
!
|
|
! no pool, just copy old variables on the new ones
|
|
!
|
|
nksqtot=nksq
|
|
xk_collect(:,1:nks) = xk(:,1:nks)
|
|
el_ph_mat_collect => el_ph_mat
|
|
ELSE
|
|
!
|
|
! pools, allocate new variables and collect the results. All the rest
|
|
! remain unchanged.
|
|
!
|
|
IF (lgamma) THEN
|
|
nksqtot=nkstot
|
|
ELSE
|
|
nksqtot=nkstot/2
|
|
ENDIF
|
|
ALLOCATE(el_ph_mat_collect(nbnd,nbnd,nksqtot,3*nat))
|
|
! FIXME: these two routines should be replaced by a generic routine
|
|
CALL xk_wk_collect(xk_collect,xk,nkstot,nks)
|
|
CALL el_ph_collect(3*nat,el_ph_mat,el_ph_mat_collect,nksqtot,nksq)
|
|
ENDIF
|
|
!
|
|
! read eigenvalues for the dense grid
|
|
! FIXME: this should be done from the xml file, not from a specialized file
|
|
! parallel case: only first node reads
|
|
!
|
|
IF ( ionode ) THEN
|
|
tmp_dir=tmp_dir_save
|
|
CALL seqopn( iuna2Fsave, 'a2Fsave', 'FORMATTED', exst )
|
|
tmp_dir=tmp_dir_phq
|
|
READ(iuna2Fsave,*) ibnd, nksfit
|
|
END IF
|
|
!
|
|
CALL mp_bcast (ibnd, ionode_id, intra_image_comm)
|
|
CALL mp_bcast (nksfit, ionode_id, intra_image_comm)
|
|
if ( ibnd /= nbnd ) call errore('elphsum','wrong file read',iuna2Fsave)
|
|
allocate (etfit(nbnd,nksfit), xkfit(3,nksfit), wkfit(nksfit))
|
|
!
|
|
IF ( ionode ) THEN
|
|
READ(iuna2Fsave,*) etfit
|
|
READ(iuna2Fsave,*) ((xkfit(i,ik), i=1,3), ik=1,nksfit)
|
|
READ(iuna2Fsave,*) wkfit
|
|
READ(iuna2Fsave,*) nk1fit, nk2fit, nk3fit
|
|
CLOSE( UNIT = iuna2Fsave, STATUS = 'KEEP' )
|
|
END IF
|
|
!
|
|
! broadcast all variables read
|
|
!
|
|
CALL mp_bcast (etfit, ionode_id, intra_image_comm)
|
|
CALL mp_bcast (xkfit, ionode_id, intra_image_comm)
|
|
CALL mp_bcast (wkfit, ionode_id, intra_image_comm)
|
|
CALL mp_bcast (nk1fit, ionode_id, intra_image_comm)
|
|
CALL mp_bcast (nk2fit, ionode_id, intra_image_comm)
|
|
CALL mp_bcast (nk3fit, ionode_id, intra_image_comm)
|
|
!
|
|
nkfit=nk1fit*nk2fit*nk3fit
|
|
!
|
|
! efermig and dos_ef require scattered points and eigenvalues
|
|
! isk is neither read nor used. phonon with two Fermi energies is
|
|
! not yet implemented.
|
|
!
|
|
nksfit_dist = ( nksfit / npool )
|
|
rest = ( nksfit - nksfit_dist * npool )
|
|
IF ( ( my_pool_id + 1 ) <= rest ) nksfit_dist = nksfit_dist + 1
|
|
kunit_save=kunit
|
|
kunit=1
|
|
|
|
#ifdef __MPI
|
|
ALLOCATE(etfit_dist(nbnd,nksfit_dist))
|
|
ALLOCATE(wkfit_dist(nksfit_dist))
|
|
CALL poolscatter( 1, nksfit, wkfit, nksfit_dist, wkfit_dist )
|
|
CALL poolscatter( nbnd, nksfit, etfit, nksfit_dist, etfit_dist )
|
|
#else
|
|
wkfit_dist => wkfit
|
|
etfit_dist => etfit
|
|
#endif
|
|
!
|
|
do isig=1,nsig
|
|
!
|
|
! recalculate Ef = effit and DOS at Ef N(Ef) = dosfit using dense grid
|
|
! for value "deg" of gaussian broadening
|
|
!
|
|
deg(isig) = isig * el_ph_sigma
|
|
!
|
|
effit(isig) = efermig &
|
|
( etfit_dist, nbnd, nksfit_dist, nelec, wkfit_dist, &
|
|
deg(isig), ngauss1, 0, isk)
|
|
dosfit(isig) = dos_ef ( ngauss1, deg(isig), effit(isig), etfit_dist, &
|
|
wkfit_dist, nksfit_dist, nbnd) / 2.0d0
|
|
enddo
|
|
#ifdef __MPI
|
|
DEALLOCATE(etfit_dist)
|
|
DEALLOCATE(wkfit_dist)
|
|
#endif
|
|
kunit=kunit_save
|
|
allocate (eqkfit(nkfit), eqqfit(nkfit), sfit(nkfit))
|
|
!
|
|
! map k-points in the IBZ to k-points in the complete uniform grid
|
|
!
|
|
nksfit_real=nksfit/nspin_lsda
|
|
call lint ( nsym, s, .true., at, bg, npk, 0,0,0, &
|
|
nk1fit,nk2fit,nk3fit, nksfit_real, xkfit, 1, nkfit, eqkfit, sfit)
|
|
deallocate (sfit, xkfit, wkfit)
|
|
!
|
|
! find epsilon(k+q) in the dense grid
|
|
!
|
|
call cryst_to_cart (1, xq, at, -1)
|
|
qx = nint(nk1fit*xq(1))
|
|
if (abs(qx-nk1fit*xq(1)) > eps) &
|
|
call errore('elphsum','q is not a vector in the dense grid',1)
|
|
if (qx < 0) qx = qx + nk1fit
|
|
if (qx > nk1fit) qx = qx - nk1fit
|
|
qy = nint(nk2fit*xq(2))
|
|
if (abs(qy-nk2fit*xq(2)) > eps) &
|
|
call errore('elphsum','q is not a vector in the dense grid',2)
|
|
if (qy < 0) qy = qy + nk2fit
|
|
if (qy > nk2fit) qy = qy - nk2fit
|
|
qz = nint(nk3fit*xq(3))
|
|
if (abs(qz-nk3fit*xq(3)) > eps) &
|
|
call errore('elphsum','q is not a vector in the dense grid',3)
|
|
if (qz < 0) qz = qz + nk3fit
|
|
if (qz > nk3fit) qz = qz - nk3fit
|
|
call cryst_to_cart (1, xq, bg, 1)
|
|
!
|
|
eqqfit(:) = 0
|
|
do i=1,nk1fit
|
|
do j=1,nk2fit
|
|
do k=1,nk3fit
|
|
ik = k-1 + (j-1)*nk3fit + (i-1)*nk2fit*nk3fit + 1
|
|
iq = i+qx
|
|
if (iq > nk1fit) iq = iq - nk1fit
|
|
jq = j+qy
|
|
if (jq > nk2fit) jq = jq - nk2fit
|
|
kq = k+qz
|
|
if (kq > nk3fit) kq = kq - nk3fit
|
|
nn = (kq-1)+(jq-1)*nk3fit+(iq-1)*nk2fit*nk3fit + 1
|
|
eqqfit(ik) = eqkfit(nn)
|
|
enddo
|
|
enddo
|
|
enddo
|
|
!
|
|
! calculate the electron-phonon coefficient using the dense grid
|
|
!
|
|
nti = nk1fit/nk1
|
|
ntj = nk2fit/nk2
|
|
ntk = nk3fit/nk3
|
|
nkBZ = nk1*nk2*nk3
|
|
allocate (eqBZ(nkBZ), sBZ(nkBZ))
|
|
!
|
|
nks_real=nkstot/nspin_lsda
|
|
IF ( lgamma ) THEN
|
|
call lint ( nsymq, s, minus_q, at, bg, npk, 0,0,0, &
|
|
nk1,nk2,nk3, nks_real, xk_collect, 1, nkBZ, eqBZ, sBZ)
|
|
ELSE
|
|
call lint ( nsymq, s, minus_q, at, bg, npk, 0,0,0, &
|
|
nk1,nk2,nk3, nks_real, xk_collect, 2, nkBZ, eqBZ, sBZ)
|
|
END IF
|
|
!
|
|
allocate (gf(3*nat,3*nat,nsig))
|
|
gf = (0.0d0,0.0d0)
|
|
!
|
|
wqa = 1.0d0/nkfit
|
|
IF (nspin==1) wqa=degspin*wqa
|
|
!
|
|
do ibnd = 1, nbnd
|
|
do jbnd = 1, nbnd
|
|
allocate (g2(nkBZ*nspin_lsda,3*nat,3*nat))
|
|
allocate (g1(nksqtot,3*nat,3*nat))
|
|
do ik = 1, nksqtot
|
|
do ii = 1, 3*nat
|
|
do jj = 1, 3*nat
|
|
g1(ik,ii,jj)=CONJG(el_ph_mat_collect(jbnd,ibnd,ik,ii))* &
|
|
el_ph_mat_collect(jbnd,ibnd,ik,jj)
|
|
enddo ! ipert
|
|
enddo !jpert
|
|
enddo ! ik
|
|
!
|
|
allocate (g0(3*nat,3*nat))
|
|
do i=1,nk1
|
|
do j=1,nk2
|
|
do k=1,nk3
|
|
do ispin=1,nspin_lsda
|
|
nn = k-1 + (j-1)*nk3 + (i-1)*nk2*nk3 + 1
|
|
itemp1 = eqBZ(nn)
|
|
if (ispin==2) itemp1=itemp1+nksqtot/2
|
|
g0(:,:) = g1(itemp1,:,:)
|
|
itemp2 = sBZ(nn)
|
|
call symm ( g0, u, xq, s, itemp2, rtau, irt, &
|
|
at, bg, nat)
|
|
if (ispin==2) nn=nn+nkBZ
|
|
g2(nn,:,:) = g0(:,:)
|
|
enddo
|
|
enddo ! k
|
|
enddo !j
|
|
enddo !i
|
|
deallocate (g0)
|
|
deallocate (g1)
|
|
!
|
|
allocate ( point(nkBZ), noint(nkfit), ctemp(nkfit) )
|
|
do jpert = 1, 3 * nat
|
|
do ipert = 1, 3 * nat
|
|
do ispin=1,nspin_lsda
|
|
!
|
|
point(1:nkBZ) = &
|
|
g2(1+nkBZ*(ispin-1):nkBZ+nkBZ*(ispin-1),ipert,jpert)
|
|
!
|
|
CALL clinear(nk1,nk2,nk3,nti,ntj,ntk,point,noint)
|
|
!
|
|
do isig = 1, nsig
|
|
degauss1 = deg(isig)
|
|
do ik=1,nkfit
|
|
etk = etfit(ibnd,eqkfit(ik)+nksfit*(ispin-1)/2)
|
|
etq = etfit(jbnd,eqqfit(ik)+nksfit*(ispin-1)/2)
|
|
w0g1 = w0gauss( (effit(isig)-etk) &
|
|
/ degauss1,ngauss1) / degauss1
|
|
w0g2 = w0gauss( (effit(isig)-etq) &
|
|
/ degauss1,ngauss1) / degauss1
|
|
ctemp(ik) = noint(ik)* wqa * w0g1 * w0g2
|
|
enddo
|
|
gf(ipert,jpert,isig) = gf(ipert,jpert,isig) + &
|
|
SUM (ctemp)
|
|
enddo ! isig
|
|
enddo ! ispin
|
|
enddo ! ipert
|
|
enddo !jpert
|
|
deallocate (point, noint, ctemp)
|
|
deallocate (g2)
|
|
!
|
|
enddo ! ibnd
|
|
enddo ! jbnd
|
|
|
|
deallocate (eqqfit, eqkfit)
|
|
deallocate (etfit)
|
|
deallocate (eqBZ, sBZ)
|
|
!
|
|
allocate (gam(3*nat,nsig), lamb(3*nat,nsig))
|
|
lamb(:,:) = 0.0d0
|
|
gam (:,:) = 0.0d0
|
|
do isig= 1,nsig
|
|
do nu = 1,3*nat
|
|
gam(nu,isig) = 0.0d0
|
|
do mu = 1, 3 * nat
|
|
do vu = 1, 3 * nat
|
|
gam(nu,isig) = gam(nu,isig) + DBLE(conjg(dyn(mu,nu)) * &
|
|
gf(mu,vu,isig) * dyn(vu,nu))
|
|
enddo
|
|
enddo
|
|
gam(nu,isig) = gam(nu,isig) * pi/2.0d0
|
|
!
|
|
! the factor 2 comes from the factor sqrt(hbar/2/M/omega) that appears
|
|
! in the definition of the electron-phonon matrix element g
|
|
! The sqrt(1/M) factor is actually hidden into the normal modes
|
|
!
|
|
! gamma = \pi \sum_k\sum_{i,j} \delta(e_{k,i}-Ef) \delta(e_{k+q,j}-Ef)
|
|
! | \sum_mu z(mu,nu) <psi_{k+q,j}|dvscf_q(mu)*psi_{k,i}> |^2
|
|
! where z(mu,nu) is the mu component of normal mode nu (z = dyn)
|
|
! gamma(nu) is the phonon linewidth of mode nu
|
|
!
|
|
! The factor N(Ef)^2 that appears in most formulations of el-ph interact
|
|
! is absent because we sum, not average, over the Fermi surface.
|
|
! The factor 2 is provided by the sum over spins
|
|
!
|
|
if (sqrt(abs(w2(nu))) > epsw) then
|
|
! lambda is the adimensional el-ph coupling for mode nu:
|
|
! lambda(nu)= gamma(nu)/(pi N(Ef) \omega_{q,nu}^2)
|
|
lamb(nu,isig) = gam(nu,isig)/pi/w2(nu)/dosfit(isig)
|
|
else
|
|
lamb(nu,isig) = 0.0d0
|
|
endif
|
|
gam(nu,isig) = gam(nu,isig)*ry_to_ghz
|
|
enddo !nu
|
|
enddo ! isig
|
|
!
|
|
do isig= 1,nsig
|
|
WRITE (6, 9000) deg(isig), ngauss1
|
|
WRITE (6, 9005) dosfit(isig), effit(isig) * rytoev
|
|
do nu=1,3*nat
|
|
WRITE (6, 9010) nu, lamb(nu,isig), gam(nu,isig)
|
|
enddo
|
|
enddo
|
|
! Isaev: save files in suitable format for processing by lambda.x
|
|
name=TRIM(elph_dir)// 'elph.inp_lambda.' //TRIM(int_to_char(current_iq))
|
|
|
|
IF (ionode) THEN
|
|
open(unit=12, file=TRIM(name), form='formatted', status='unknown', &
|
|
iostat=ios)
|
|
|
|
write(12, "(5x,3f14.6,2i6)") xq(1),xq(2),xq(3), nsig, 3*nat
|
|
write(12, "(6e14.6)") (w2(i), i=1,3*nat)
|
|
|
|
do isig= 1,nsig
|
|
WRITE (12, 9000) deg(isig), ngauss1
|
|
WRITE (12, 9005) dosfit(isig), effit(isig) * rytoev
|
|
do nu=1,3*nat
|
|
WRITE (12, 9010) nu, lamb(nu,isig), gam(nu,isig)
|
|
enddo
|
|
enddo
|
|
close (unit=12,status='keep')
|
|
ENDIF
|
|
! Isaev end
|
|
CALL mp_bcast(ios, ionode_id, intra_image_comm)
|
|
IF (ios /= 0) CALL errore('elphsum','problem opening file'//TRIM(name),1)
|
|
deallocate (gam)
|
|
deallocate (lamb)
|
|
write(stdout,*)
|
|
!
|
|
! Prepare interface to q2r and matdyn
|
|
!
|
|
call star_q (xq, at, bg, nsym, s, invs, nq, sxq, isq, imq, .TRUE. )
|
|
!
|
|
do isig=1,nsig
|
|
name=TRIM(elph_dir)//'a2Fq2r.'// TRIM(int_to_char(50 + isig)) &
|
|
//'.'//TRIM(int_to_char(current_iq))
|
|
if (ionode) then
|
|
iuelph = 4
|
|
open(iuelph, file=name, STATUS = 'unknown', FORM = 'formatted', &
|
|
iostat=ios)
|
|
else
|
|
!
|
|
! this node doesn't write: unit 6 is redirected to /dev/null
|
|
!
|
|
iuelph =6
|
|
end if
|
|
call mp_bcast(ios, ionode_id, intra_image_comm)
|
|
IF (ios /= 0) call errore('elphsum','opening output file '// TRIM(name),1)
|
|
dyn22(:,:) = gf(:,:,isig)
|
|
write(iuelph,*) deg(isig), effit(isig), dosfit(isig)
|
|
IF ( imq == 0 ) THEN
|
|
write(iuelph,*) 2*nq
|
|
ELSE
|
|
write(iuelph,*) nq
|
|
ENDIF
|
|
xmldyn_save=xmldyn
|
|
xmldyn=.FALSE.
|
|
call q2qstar_ph (dyn22, at, bg, nat, nsym, s, invs, &
|
|
irt, rtau, nq, sxq, isq, imq, iuelph)
|
|
xmldyn=xmldyn_save
|
|
if (ionode) CLOSE( UNIT = iuelph, STATUS = 'KEEP' )
|
|
enddo
|
|
deallocate (gf)
|
|
DEALLOCATE( deg )
|
|
DEALLOCATE( effit )
|
|
DEALLOCATE( dosfit )
|
|
DEALLOCATE(xk_collect)
|
|
IF (npool /= 1) DEALLOCATE(el_ph_mat_collect)
|
|
|
|
!
|
|
9000 FORMAT(5x,'Gaussian Broadening: ',f7.3,' Ry, ngauss=',i4)
|
|
9005 FORMAT(5x,'DOS =',f10.6,' states/spin/Ry/Unit Cell at Ef=', &
|
|
& f10.6,' eV')
|
|
9006 FORMAT(5x,'double delta at Ef =',f10.6)
|
|
9010 FORMAT(5x,'lambda(',i5,')=',f8.4,' gamma=',f8.2,' GHz')
|
|
!
|
|
RETURN
|
|
END SUBROUTINE elphsum
|
|
|
|
!-----------------------------------------------------------------------
|
|
SUBROUTINE elphsum_simple
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! Sum over BZ of the electron-phonon matrix elements el_ph_mat
|
|
! Original routine written by Francesco Mauri
|
|
! Rewritten by Matteo Calandra
|
|
!-----------------------------------------------------------------------
|
|
USE kinds, ONLY : DP
|
|
USE constants, ONLY : pi, ry_to_cmm1, ry_to_ghz, rytoev
|
|
USE ions_base, ONLY : nat
|
|
USE cell_base, ONLY : at, bg
|
|
USE symm_base, ONLY : s, irt, nsym, invs
|
|
USE klist, ONLY : xk, nelec, nks, wk
|
|
USE wvfct, ONLY : nbnd, et
|
|
USE el_phon, ONLY : el_ph_mat, el_ph_nsigma, el_ph_ngauss, el_ph_sigma
|
|
USE mp_pools, ONLY : inter_pool_comm, npool
|
|
USE mp_images, ONLY : intra_image_comm
|
|
USE output, ONLY : fildyn
|
|
USE dynmat, ONLY : dyn, w2
|
|
USE modes, ONLY : u, nirr
|
|
USE control_ph, only : current_iq, qplot
|
|
USE lsda_mod, only : isk
|
|
USE el_phon, ONLY : done_elph, gamma_disp
|
|
USE io_global, ONLY : stdout, ionode, ionode_id
|
|
USE mp, ONLY: mp_sum, mp_bcast
|
|
|
|
USE lr_symm_base, ONLY : rtau, nsymq, irotmq, minus_q
|
|
USE qpoint, ONLY : xq, nksq, ikks, ikqs
|
|
!
|
|
IMPLICIT NONE
|
|
REAL(DP), PARAMETER :: eps = 20_dp/ry_to_cmm1 ! eps = 20 cm^-1, in Ry
|
|
!
|
|
INTEGER :: ik, ikk, ikq, isig, ibnd, jbnd, ipert, jpert, nu, mu, &
|
|
vu, ngauss1, nsig, iuelph, ios, irr
|
|
INTEGER :: nmodes
|
|
REAL(DP) :: weight, w0g1, w0g2, w0gauss, wgauss, degauss1, dosef, &
|
|
ef1, phase_space, lambda, gamma
|
|
REAL(DP), EXTERNAL :: dos_ef, efermig
|
|
character(len=80) :: filelph
|
|
CHARACTER(len=256) :: file_elphmat
|
|
!
|
|
COMPLEX(DP) :: el_ph_sum (3*nat,3*nat), dyn_corr(3*nat,3*nat)
|
|
|
|
INTEGER, EXTERNAL :: find_free_unit
|
|
CHARACTER(LEN=6) :: int_to_char
|
|
|
|
|
|
DO irr=1,nirr
|
|
IF (.NOT.done_elph(irr)) RETURN
|
|
ENDDO
|
|
|
|
nmodes=3*nat
|
|
|
|
filelph=TRIM(fildyn)//'.elph.'//TRIM(int_to_char(current_iq))
|
|
|
|
! parallel case: only first node writes
|
|
IF ( ionode ) THEN
|
|
!
|
|
iuelph = find_free_unit()
|
|
OPEN (unit = iuelph, file = TRIM(filelph), status = 'unknown', err = &
|
|
100, iostat = ios)
|
|
REWIND (iuelph)
|
|
ELSE
|
|
iuelph = 0
|
|
!
|
|
END IF
|
|
100 CONTINUE
|
|
CALL mp_bcast(ios,ionode_id,intra_image_comm)
|
|
CALL errore ('elphsum_simple', 'opening file '//filelph, ABS (ios) )
|
|
|
|
IF (ionode) THEN
|
|
WRITE (iuelph, '(3f15.8,2i8)') xq, nsig, 3 * nat
|
|
WRITE (iuelph, '(6e14.6)') (w2 (nu) , nu = 1, nmodes)
|
|
ENDIF
|
|
|
|
|
|
ngauss1=0
|
|
DO isig = 1, el_ph_nsigma
|
|
! degauss1 = 0.01 * isig
|
|
degauss1 = el_ph_sigma * isig
|
|
el_ph_sum(:,:) = (0.d0, 0.d0)
|
|
phase_space = 0.d0
|
|
!
|
|
! Recalculate the Fermi energy Ef=ef1 and the DOS at Ef, dosef = N(Ef)
|
|
! for this gaussian broadening
|
|
!
|
|
! Note that the weights of k+q points must be set to zero for the
|
|
! following call to yield correct results
|
|
!
|
|
|
|
ef1 = efermig (et, nbnd, nks, nelec, wk, degauss1, el_ph_ngauss, 0, isk)
|
|
dosef = dos_ef (el_ph_ngauss, degauss1, ef1, et, wk, nks, nbnd)
|
|
! N(Ef) is the DOS per spin, not summed over spin
|
|
dosef = dosef / 2.d0
|
|
!
|
|
! Sum over bands with gaussian weights
|
|
!
|
|
|
|
DO ik = 1, nksq
|
|
|
|
!
|
|
! see subroutine elphel for the logic of indices
|
|
!
|
|
ikk = ikks(ik)
|
|
ikq = ikqs(ik)
|
|
DO ibnd = 1, nbnd
|
|
w0g1 = w0gauss ( (ef1 - et (ibnd, ikk) ) / degauss1, ngauss1) &
|
|
/ degauss1
|
|
DO jbnd = 1, nbnd
|
|
w0g2 = w0gauss ( (ef1 - et (jbnd, ikq) ) / degauss1, ngauss1) &
|
|
/ degauss1
|
|
! note that wk(ikq)=wk(ikk)
|
|
weight = wk (ikk) * w0g1 * w0g2
|
|
DO jpert = 1, 3 * nat
|
|
DO ipert = 1, 3 * nat
|
|
el_ph_sum (ipert, jpert) = el_ph_sum (ipert, jpert) + weight * &
|
|
CONJG (el_ph_mat (jbnd, ibnd, ik, ipert) ) * &
|
|
el_ph_mat (jbnd, ibnd, ik, jpert)
|
|
ENDDO
|
|
ENDDO
|
|
phase_space = phase_space+weight
|
|
ENDDO
|
|
ENDDO
|
|
|
|
ENDDO
|
|
|
|
! el_ph_sum(mu,nu)=\sum_k\sum_{i,j}[ <psi_{k+q,j}|dvscf_q(mu)*psi_{k,i}>
|
|
! x <psi_{k+q,j}|dvscf_q(nu)*psi_{k,i}>
|
|
! x \delta(e_{k,i}-Ef) \delta(e_{k+q,j}
|
|
!
|
|
! collect contributions from all pools (sum over k-points)
|
|
!
|
|
|
|
call mp_sum ( el_ph_sum , inter_pool_comm )
|
|
call mp_sum ( phase_space , inter_pool_comm )
|
|
|
|
!
|
|
! symmetrize el_ph_sum(mu,nu) : it transforms as the dynamical matrix
|
|
!
|
|
|
|
CALL symdyn_munu_new (el_ph_sum, u, xq, s, invs, rtau, irt, at, &
|
|
bg, nsymq, nat, irotmq, minus_q)
|
|
!
|
|
WRITE (stdout, *)
|
|
WRITE (stdout, 9000) degauss1, ngauss1
|
|
WRITE (stdout, 9005) dosef, ef1 * rytoev
|
|
WRITE (stdout, 9006) phase_space
|
|
IF (ionode) THEN
|
|
WRITE (iuelph, 9000) degauss1, ngauss1
|
|
WRITE (iuelph, 9005) dosef, ef1 * rytoev
|
|
ENDIF
|
|
|
|
DO nu = 1, nmodes
|
|
gamma = 0.d0
|
|
DO mu = 1, 3 * nat
|
|
DO vu = 1, 3 * nat
|
|
gamma = gamma + DBLE (CONJG (dyn (mu, nu) ) * el_ph_sum (mu, vu)&
|
|
* dyn (vu, nu) )
|
|
ENDDO
|
|
ENDDO
|
|
gamma = pi * gamma / 2.d0
|
|
!
|
|
! the factor 2 comes from the factor sqrt(hbar/2/M/omega) that appears
|
|
! in the definition of the electron-phonon matrix element g
|
|
! The sqrt(1/M) factor is actually hidden into the normal modes
|
|
!
|
|
! gamma = \pi \sum_k\sum_{i,j} \delta(e_{k,i}-Ef) \delta(e_{k+q,j}-Ef)
|
|
! | \sum_mu z(mu,nu) <psi_{k+q,j}|dvscf_q(mu)*psi_{k,i}> |^2
|
|
! where z(mu,nu) is the mu component of normal mode nu (z = dyn)
|
|
! gamma(nu) is the phonon linewidth of mode nu
|
|
!
|
|
! The factor N(Ef)^2 that appears in most formulations of el-ph interact
|
|
! is absent because we sum, not average, over the Fermi surface.
|
|
! The factor 2 is provided by the sum over spins
|
|
!
|
|
IF (SQRT (ABS (w2 (nu) ) ) > eps) THEN
|
|
! lambda is the adimensional el-ph coupling for mode nu:
|
|
! lambda(nu)= gamma(nu)/(pi N(Ef) \omega_{q,nu}^2)
|
|
lambda = gamma / pi / w2 (nu) / dosef
|
|
ELSE
|
|
lambda = 0.d0
|
|
ENDIF
|
|
WRITE (stdout, 9010) nu, lambda, gamma * ry_to_gHz
|
|
IF (ionode) WRITE (iuelph, 9010) nu, lambda, gamma * ry_to_gHz
|
|
IF (qplot) gamma_disp(nu,isig,current_iq) = gamma * ry_to_gHz
|
|
ENDDO
|
|
ENDDO
|
|
|
|
|
|
9000 FORMAT(5x,'Gaussian Broadening: ',f7.3,' Ry, ngauss=',i4)
|
|
9005 FORMAT(5x,'DOS =',f10.6,' states/spin/Ry/Unit Cell at Ef=', &
|
|
& f10.6,' eV')
|
|
9006 FORMAT(5x,'double delta at Ef =',f10.6)
|
|
9010 FORMAT(5x,'lambda(',i5,')=',f8.4,' gamma=',f8.2,' GHz')
|
|
!
|
|
!
|
|
IF (ionode) CLOSE (unit = iuelph)
|
|
RETURN
|
|
|
|
|
|
|
|
! call star_q(x_q(1,iq), at, bg, nsym , s , invs , nq, sxq, &
|
|
! isq, imq, .FALSE. )
|
|
|
|
|
|
END SUBROUTINE elphsum_simple
|
|
|
|
!-----------------------------------------------------------------------
|
|
FUNCTION dos_ef (ngauss, degauss, ef, et, wk, nks, nbnd)
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
USE kinds, ONLY : DP
|
|
USE mp_pools, ONLY : inter_pool_comm
|
|
USE mp, ONLY : mp_sum
|
|
IMPLICIT NONE
|
|
REAL(DP) :: dos_ef
|
|
INTEGER :: ngauss, nbnd, nks
|
|
REAL(DP) :: et (nbnd, nks), wk (nks), ef, degauss
|
|
!
|
|
INTEGER :: ik, ibnd
|
|
REAL(DP), EXTERNAL :: w0gauss
|
|
!
|
|
! Compute DOS at E_F (states per Ry per unit cell)
|
|
!
|
|
dos_ef = 0.0d0
|
|
DO ik = 1, nks
|
|
DO ibnd = 1, nbnd
|
|
dos_ef = dos_ef + wk (ik) * w0gauss ( (et (ibnd, ik) - ef) &
|
|
/ degauss, ngauss) / degauss
|
|
ENDDO
|
|
ENDDO
|
|
!
|
|
! Collects partial sums on k-points from all pools
|
|
!
|
|
CALL mp_sum ( dos_ef, inter_pool_comm )
|
|
!
|
|
RETURN
|
|
END FUNCTION dos_ef
|
|
|
|
!a2F
|
|
subroutine lint ( nsym, s, minus_q, at, bg, npk, k1,k2,k3, &
|
|
nk1,nk2,nk3, nks, xk, kunit, nkBZ, eqBZ, sBZ)
|
|
!-----------------------------------------------------------------------
|
|
!
|
|
! Find which k-points of a uniform grid are in the IBZ
|
|
!
|
|
use kinds, only : DP
|
|
implicit none
|
|
integer, intent (IN) :: nks, nsym, s(3,3,48), npk, k1, k2, k3, &
|
|
nk1, nk2, nk3, kunit, nkBZ
|
|
logical, intent (IN) :: minus_q
|
|
real(kind=DP), intent(IN):: at(3,3), bg(3,3), xk(3,npk)
|
|
integer, INTENT(OUT) :: eqBZ(nkBZ), sBZ(nkBZ)
|
|
!
|
|
real(kind=DP) :: xkr(3), deltap(3), deltam(3)
|
|
real(kind=DP), parameter:: eps=1.0d-5
|
|
real(kind=DP), allocatable :: xkg(:,:), xp(:,:)
|
|
integer :: i,j,k, ns, n, nk
|
|
integer :: nkh
|
|
!
|
|
! Re-generate a uniform grid of k-points xkg
|
|
!
|
|
allocate (xkg( 3,nkBZ))
|
|
!
|
|
if(kunit < 1 .or. kunit > 2) call errore('lint','bad kunit value',kunit)
|
|
!
|
|
! kunit=2: get only "true" k points, not k+q points, from the list
|
|
!
|
|
nkh = nks/kunit
|
|
allocate (xp(3,nkh))
|
|
if (kunit == 1) then
|
|
xp(:,1:nkh) = xk(:,1:nkh)
|
|
else
|
|
do j=1,nkh
|
|
xp(:,j) = xk(:,2*j-1)
|
|
enddo
|
|
end if
|
|
do i=1,nk1
|
|
do j=1,nk2
|
|
do k=1,nk3
|
|
n = (k-1) + (j-1)*nk3 + (i-1)*nk2*nk3 + 1
|
|
xkg(1,n) = dble(i-1)/nk1 + dble(k1)/2/nk1
|
|
xkg(2,n) = dble(j-1)/nk2 + dble(k2)/2/nk2
|
|
xkg(3,n) = dble(k-1)/nk3 + dble(k3)/2/nk3
|
|
end do
|
|
end do
|
|
end do
|
|
|
|
call cryst_to_cart (nkh,xp,at,-1)
|
|
|
|
do nk=1,nkBZ
|
|
do n=1,nkh
|
|
do ns=1,nsym
|
|
do i=1,3
|
|
xkr(i) = s(i,1,ns) * xp(1,n) + &
|
|
s(i,2,ns) * xp(2,n) + &
|
|
s(i,3,ns) * xp(3,n)
|
|
end do
|
|
do i=1,3
|
|
deltap(i) = xkr(i)-xkg(i,nk) - nint (xkr(i)-xkg(i,nk) )
|
|
deltam(i) = xkr(i)+xkg(i,nk) - nint (xkr(i)+xkg(i,nk) )
|
|
end do
|
|
if ( sqrt ( deltap(1)**2 + &
|
|
deltap(2)**2 + &
|
|
deltap(3)**2 ) < eps .or. ( minus_q .and. &
|
|
sqrt ( deltam(1)**2 + &
|
|
deltam(2)**2 + &
|
|
deltam(3)**2 ) < eps ) ) then
|
|
eqBZ(nk) = n
|
|
sBZ(nk) = ns
|
|
go to 15
|
|
end if
|
|
end do
|
|
end do
|
|
call errore('lint','cannot locate k point xk',nk)
|
|
15 continue
|
|
end do
|
|
|
|
do n=1,nkh
|
|
do nk=1,nkBZ
|
|
if (eqBZ(nk) == n) go to 20
|
|
end do
|
|
! this failure of the algorithm may indicate that the displaced grid
|
|
! (with k1,k2,k3.ne.0) does not have the full symmetry of the lattice
|
|
call errore('lint','cannot remap grid on k-point list',n)
|
|
20 continue
|
|
end do
|
|
|
|
deallocate(xkg)
|
|
deallocate(xp)
|
|
|
|
return
|
|
end subroutine lint
|