EPW input files for Si example

[akentphonon]

Dear Nakib,

Thank you for this very useful code.

I am trying reproduce Si example within elphbolt from scratch - by performing calculations for ifcs and electron-phonons elements with QE and EPW. I have some doubts about EPW step - what the specific tags needed to print electron-phonons elements within EPW calculations. If possible would you please share EPW input file with me.

Thanks
Alex

[nakib]

Dear Alex,

Thank you for your interest in elphbolt!

I have provided two modified EPW source files in the repository. You will have to put these files in your EPW/src directory and rebuild EPW. Below I share the EPW input file that will print out all the Wannier space information that elphbolt requires. You can adapt it for your own calculation.

Note that EPW requires you to first do a phonon calculation with Quantum Espresso. Following that, you need to do a post-processing step with a script called pp.py that comes with EPW. You can look at the examples that ship with the EPW code and look at some tutorials to know more about how to do an EPW calculation. The EPW forum can give you more support on that.

Let me know if something is unclear. :)

Best,
Nakib

epw.in:

&inputepw
  prefix = 'si'
  amass(1) = 28.086
  asr_typ = 'simple'

  outdir = '<enter epw output directory>'

  elph  = .t.
  kmaps = .f. 
  epbwrite = .t. 
  epbread = .f.
  etf_mem = 1
  epwwrite = .t. 
  epwread = .f. 

  nbndsub = 8

  wannierize  = .t. 
  num_iter = 1000
  dis_win_max = 17.5
  dis_froz_max = 9.5
  proj(1) = 'Si:sp3' ! 4 valence + 4 conduction bands

  wdata(1) = 'conv_tol = 1.0E-12'
  wdata(2) = 'dis_num_iter = 600'
  wdata(3) = 'dis_mix_ratio = 0.5d0'
  wdata(4) = 'dis_conv_tol = 1.0d-11'
  wdata(5) = 'num_print_cycles  = 50'

  elecselfen  = .false.
  phonselfen  = .false.
  a2f  = .false.

  dvscf_dir   = '<enter phonon "save" directory>'
 
  nk1         = 12
  nk2         = 12
  nk3         = 12
  nq1         = 6
  nq2         = 6
  nq3         = 6
 /
   16 cartesian
   0.000000000   0.000000000   0.000000000
  -0.166666667   0.166666667  -0.166666667
  -0.333333333   0.333333333  -0.333333333
   0.500000000  -0.500000000   0.500000000
   0.000000000   0.333333333   0.000000000
  -0.166666667   0.500000000  -0.166666667
   0.666666667  -0.333333333   0.666666667
   0.500000000  -0.166666667   0.500000000
   0.333333333   0.000000000   0.333333333
   0.000000000   0.666666667   0.000000000
   0.833333333  -0.166666667   0.833333333
   0.666666667  -0.000000000   0.666666667
   0.000000000  -1.000000000   0.000000000
   0.666666667  -0.333333333   1.000000000
   0.500000000  -0.166666667   0.833333333
  -0.333333333  -1.000000000   0.000000000

[akentphonon]

Thanks Nakib!

Your suggestions are very helpful. I will give them a go - I might bother you more queries later.

Thanks,
Alex