EPW Forum

Posted: **Thu Jan 26, 2023 8:55 am**

Dear Friends，

I'm a newcomer to the EPW calculation, and I face an issue while doing EPW calculation.
I use EPW and QE to calculate electron-phonon superconductivity of 2D materials.

The electron-phonon coupling strength is very strange, about 1000. I adjusted "fsthick", wscut" and" muc" according to the standard on the forum, and the electro-acoustic coupling was reduced to 283. Obviously, this value is still very strange. Moreover, I examine the maximally localized Wannier functions. The average spatial spread of Wannier functions is just about 0.83 Å2. This should be no problem.

My friends, what might be the reason for the abnormal electron-phonon coupling strength. What should I do for it.
If the information I provided is insufficient to describe my problem, please let me know and I will provide you with the correct information.

Best regards,
mxh

Posted: **Sat Jan 28, 2023 12:42 pm**

This is my input file.

Code: Select all

&inputepw
  prefix = 'prefix'
  outdir = './tmp'
  amass(1) = xxx
  amass(2) = xxx
  amass(3) = xxx
  dvscf_dir = '../phonon3/save'

  ep_coupling = .true.
  elph        = .true.

  epwwrite    = .true.
  epwread     = .false.
  etf_mem     = 1
  
  wannierize = .true.
  nbndsub     =  8
  bands_skipped = 'exclude_bands = 1-4'

  num_iter = 500
  !dis_win_max    = 4.3
  !dis_win_min    = -20
  dis_froz_max   = -5
  !dis_froz_min   = -20
  proj(1) = 'f=0.5000001043,0.4999998808,0.58958917855:s'
  proj(2) = 'f=0.5000001043,0.0000000000,0.58958917855:s'
  proj(3) = 'f=0.0000000000,0.4999998808,0.58958917855:s'
  proj(4) = 'f=0.4999998808,0.5000001043,0.41041085125:s'
  proj(5) = 'f=0.4999998808,0.0000000000,0.41041085125:s'
  proj(6) = 'f=0.0000000000,0.5000001043,0.41041085125:s'
  proj(7) = 'C:pz'

  iverbosity  = 2

  fsthick     = 0.5  ! eV
  degaussw    = 0.1  ! eV

  fermi_plot  = .true.
  ephwrite    = .true. 
  eliashberg  = .true.

  laniso  = .true.
  limag = .true.
  lpade = .true.

  nsiter   = 500
  conv_thr_iaxis = 1.0d-3

  wscut  = 1.4 ! eV
  muc    = 0.1
  temps  = 10 20 30 40 50 60 70 80 90 100

  nk1 = 8
  nk2 = 8
  nk3 = 1

  nq1 = 4
  nq2 = 4
  nq3 = 1

  mp_mesh_k = .true.

  nkf1 = 16
  nkf2 = 16
  nkf3 = 1

  nqf1 = 8
  nqf2 = 8
  nqf3 = 1

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