EPW Forum

Dear all,

How to output the el-ph coupling strength (g2) of coarse grids without wannier interpolation in EPW?

Referring to what has been done for epmatf or epf17, I have tried g2_coarse=abs(sum(uf*epmatq))**2*inv_wq, where uf is phonon eigenvector and empatq is coarse el-ph coupling matrix as said in EPW. However, the calculated g2_coarse is different from wannier interpolated values. Then what should I do to output correct values?

Hello,

You can try to uncomment
!write(*,*)'epmatq(:,:,2,:,nqc)**2',SUM((REAL(REAL(epmatq(:,:,2,:,nqc))))**2)+&
! SUM((REAL(AIMAG(epmatq(:,:,2,:,nqc))))**2)

inside elphon_shuffle_wrap.f90

Then also print the same elements from the variable "epmatf" in ephwann_shuffle.f90

Make sure you print g and its c.c. to avoid phase issues. You also need to average on degenerate states (average all the bands, modes and k-points). Only the average on degenerate state is expected to be the same.

Best,
Samuel