mirror of https://gitlab.com/QEF/q-e.git
174 lines
5.9 KiB
Fortran
174 lines
5.9 KiB
Fortran
!
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! Copyright (C) 2002-2003 PWSCF 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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program elph
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! read files 'filelph' produced by phonon (one for each q-point)
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! sum over q-points to produce the electron-phonon coefficients:
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! lambda (the one of BCS superconductivity) and alpha^2*F(omega)
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implicit none
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integer, parameter:: npk=200, nsigx=50, nmodex=100, nex=200
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integer :: nks, ios, iuelph, ngauss, ngauss1, ngaussq, nsig, nmodes
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integer :: ik, ng, mu, nu, i
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real(8) :: q(3,npk), wk(npk), degauss(nsigx), w2(nmodex), &
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dosef(nsigx), ef(nsigx), lambdaq(nmodex,nsigx), &
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lambda(nsigx), alpha2F(nex,nsigx), logavg
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real(8) qread(3), dosef1, ef1, degauss1, gammaq, lambda2, &
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degaussq, emax, deltae, e, omega, sum
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character(len=256) :: filelph
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real(8), external :: w0gauss
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! INPUT from standard input:
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! emax degaussq ngaussq
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! nks
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! q(1,1) q(2,1) q(3,1) wk(1)
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! ... ... ... ...
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! q(1,nks) q(2,nks) q(3,nks) wk(nks)
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! filelph(1)
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! ...
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! filelph(nks)
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!
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! emax (THz) : alpha2F is plotted from 0 to "emax" in "nex" steps
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! degaussq (THz): gaussian smearing for sum over q
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! NB: not the same used in phonon !
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! ngaussq : 0 for simple gaussian, 1 for Methfessel-Paxton etc.
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! nks : number of q-points used in the sum
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! q, wk : q-points and weights
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! filelph : output files from phonon, one for each q-point
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! May contain "nsig" calculations done with different
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! broadenings for the sum over k - all of them are used
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!
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! OUTPUT in xmgr-readable format: files 'lambda.dat' and 'alpha2F.dat'
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!
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read(5,*) emax, degaussq, ngaussq
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deltae=emax/(nex-1)
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read(5,*) nks
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if (nks.gt.npk) call errore('lambda','too many q-points',npk)
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sum=0.d0
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do ik=1,nks
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read(5,*) q(1,ik), q(2,ik), q(3,ik), wk(ik)
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sum = sum + wk(ik)
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end do
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do ik=1,nks
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wk(ik)=wk(ik)/sum
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end do
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iuelph=4
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do ik=1,nks
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read(5,'(a)') filelph
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open(unit=iuelph,file=filelph,status='old',iostat=ios)
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read (iuelph,*) qread(1),qread(2),qread(3), nsig, nmodes
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if ( (qread(1)-q(1,ik))**2 + &
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(qread(2)-q(2,ik))**2 + &
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(qread(3)-q(3,ik))**2 .gt. 1.d-6) &
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call errore('lambda','inconsistent q read',ik)
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if (nsig.le.0.or.nsig.gt.nsigx) &
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call errore('lambda','wrong/too many gauss.broad.',nsigx)
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if (nmodes.le.0.or.nmodes.gt.nmodex) &
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call errore('lambda','wrong # or too many modes',nmodex)
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if (ik.eq.1) then
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do ng=1,nsig
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lambda(ng)=0.d0
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do i=1,nex
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alpha2F(i,ng)=0.d0
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end do
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end do
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end if
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! read omega^2
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read(iuelph,*) (w2(nu),nu=1,nmodes)
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! read data
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do ng=1,nsig
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read (iuelph,9000) degauss1, ngauss1
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if (ik.eq.1) then
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degauss(ng)=degauss1
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ngauss =ngauss1
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else
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if (degauss(ng).ne.degauss1.or.ngauss.ne.ngauss1) &
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call errore('lambda','inconsistent gauss.broad. read',ik)
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end if
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read (iuelph,9005) dosef1, ef1
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if (ik.eq.1) then
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dosef(ng)=dosef1
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ef(ng)=ef1
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else
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if (dosef(ng).ne.dosef1.or.ef(ng).ne.ef1) &
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call errore('lambda','inconsistent DOS(Ef) read',ik)
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end if
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do mu=1,nmodes
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read (iuelph,9010) nu, lambdaq(mu,ng), gammaq
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if (nu.ne.mu) call errore('lambda','wrong mode read',mu)
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! sum over k-points
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lambda(ng) = lambda(ng) + wk(ik)*lambdaq(mu,ng)
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do i=1,nex
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e=(i-1)*deltae
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!
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! Note that w2 is set to zero if negative to prevent NaN's
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! This may happen for acoustic modes at q=0 due to Acoustic
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! Sum Rule violation. For these phonons the contribution to
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! el-ph coupling should be zero anyway - PG 2005
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!
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! 1 Ry = 3289.828 THz
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!
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omega = sqrt( MAX( w2(mu),0.d0 ) ) * 3289.828d0
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alpha2F(i,ng) = alpha2F(i,ng) + &
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wk(ik) * lambdaq(mu,ng) * omega * 0.5d0 * &
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w0gauss((e-omega)/degaussq,ngaussq)/degaussq
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end do
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end do
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end do
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close(unit=iuelph)
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end do
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open(unit=iuelph,file='lambda.dat',status='unknown',form='formatted')
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write(iuelph,9014)
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do ng=1,nsig
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! lambda2 is used as a check
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! logavg is the logarithmic average of omega used in McMillan's formula(?)
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lambda2=0.d0
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logavg =0.d0
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do i=2,nex
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e=(i-1)*deltae
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lambda2=lambda2 + alpha2F(i,ng)/e
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logavg =logavg + alpha2F(i,ng)*log(e)/e
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end do
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lambda2=lambda2*2.d0*deltae
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logavg =logavg*2.d0 *deltae
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! 1 THz = 50 K
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logavg=exp(logavg/lambda2)*50.d0
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write(6,9015) lambda(ng), lambda2, logavg,dosef(ng),degauss(ng)
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write(iuelph,9016) &
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degauss(ng), lambda(ng), lambda2, logavg,dosef(ng)
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end do
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close(unit=iuelph)
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open(unit=iuelph,file='alpha2F.dat',status='unknown', &
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form='formatted')
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write(iuelph,9020) (degauss(ng),ng=1,nsig)
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do i=1,nex
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e=(i-1)*deltae
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write(iuelph,9025) e,(alpha2F(i,ng),ng=1,nsig)
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end do
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close(unit=iuelph)
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stop
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9000 format(5x,'Gaussian Broadening: ',f7.3,' Ry, ngauss=',i4)
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9005 format(5x,'DOS =',f10.6,' states/spin/Ry/Unit Cell at Ef=', &
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f10.6,' eV')
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9010 format(5x,'lambda(',i2,')=',f10.6,' gamma=',f10.6,' GHz')
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9014 format('# degauss lambda int alpha2F <log w> N(Ef)')
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9015 format(5x,'lambda =',f9.6,' (',f10.6,') <log w>=',f9.3,'K ', &
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'N(Ef)=',f9.6,' at degauss=',f5.3)
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9016 format(f7.3,2f12.6,f10.3,2f12.6)
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9020 format('# E(THz)',10(f10.3))
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9025 format(f8.4,10(f10.5))
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end program elph
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