EPW Forum

Posted: **Mon Oct 31, 2016 4:03 pm**

Dear all,

I am trying to calculate electron-phonon coupling constants of 2D systems with spin-orbit coupling, so I prepared input files as below and ran epw v4.1 implemented in QE 6.0.

Code: Select all

--
&inputepw
  prefix      = 'B'
  amass(1)    = 10.81
  outdir      = './'

  system_2d = .true.

  elph        = .true.
  kmaps       = .false.
  epbwrite    = .true.
  epbread     = .false.

  epwwrite    = .true.
  epwread     = .false.

  nbndsub     =  18
  nbndskip    =  0

  wannierize  = .true.
  num_iter    = 500
  !dis_win_max = 21
  !dis_win_min = -3
  !dis_froz_min= -3
  !dis_froz_max= 13.5
  proj(1)     = 'B:pz'
   
  wdata(1) = ''
  wdata(2) = 'exclude_bands = 1-12'
  wdata(3) = ''
  wdata(4) = 'dis_num_iter    =  500'
  wdata(5) = 'guiding_centres = .true.'
  wdata(6) = 'bands_plot = .true.'
  wdata(7) = 'begin kpoint_path'
  wdata(8) = 'G 0 0 0 M 0.5 0 0'
  wdata(9) = 'M 0.5 0 0 K 0.3333 0.3333 0'
  wdata(10) = 'K 0.3333 0.3333 0 G 0 0 0'
  wdata(11) = 'end kpoint_path'
  wdata(12) = 'bands_plot_format = gnuplot'

  iverbosity  = 0

  !elinterp    = .true.
  !phinterp    = .true.

  !tshuffle2   = .true.
  !tphases     = .false.

  elecselfen  = .true.
  phonselfen  = .true.

  parallel_k  = .true.
  parallel_q  = .false.

  fsthick     = 6 ! eV
  eptemp      = 0.0 ! K
  degaussw    = 0.005 ! eV
  degaussq    = 0.05 !meV

  a2f         = .true.

  dvscf_dir   = '../phonons_s20_2/save'
  
  nk1         = 12
  nk2         = 12
  nk3         = 1

  nq1         = 6
  nq2         = 6
  nq3         = 1

  nkf1         = 60
  nkf2         = 60
  nkf3         = 1

  nqf1         = 60
  nqf2         = 60
  nqf3         = 1
 /
      7 cartesian
 0.0000000   0.0000000   0.0000000  0.0277778
 0.0000000   0.1924501   0.0000000  0.1666667
 0.0000000   0.3849002   0.0000000  0.1666667
 0.0000000  -0.5773503   0.0000000  0.0833333
 0.1666667   0.2886751   0.0000000  0.1666667
 0.1666667   0.4811252   0.0000000  0.3333333
 0.3333333   0.5773503   0.0000000  0.0555556

However, there was something wrong when running wannierization and program stopped with error messages.

Code: Select all

     AMN
      k points =   144 in   24 pools
            1 of    6 on ionode
            2 of    6 on ionode
            3 of    6 on ionode
            4 of    6 on ionode
            5 of    6 on ionode
            6 of    6 on ionode

     AMN calculated

     MMN
      k points =   144 in   24 pools
            1 of    6 on ionode
            2 of    6 on ionode
            3 of    6 on ionode
            4 of    6 on ionode
            5 of    6 on ionode
            6 of    6 on ionode
     MMN calculated
-------------------------------------------------------
Primary job  terminated normally, but 1 process returned
a non-zero exit code.. Per user-direction, the job has been aborted.
-------------------------------------------------------
--------------------------------------------------------------------------
mpirun detected that one or more processes exited with non-zero status, thus causing
the job to be terminated. The first process to do so was:

  Process name: [[15079,1],23]
  Exit code:    174
--------------------------------------------------------------------------

I already checked that this system can be wannierized without any problems when I used wannier.x independently.

Is there anyone who knows how to solve this problem?

Thank you.

Best regards,

Posted: **Mon Oct 31, 2016 5:17 pm**

Hello,

You can try by removing:

Code: Select all

  wdata(2) = 'exclude_bands = 1-12'

and adding the nbndskip that you need to epw (probably 12).

Best,

Samuel

Posted: **Tue Nov 01, 2016 4:41 pm**

Dear Samuel,

Thank you for nice reply and the problem is solved when the tag is removed.

However, I have another question about exclude_band tag used in wannier90.

If I want to exclude specific bands such as 1-12, 29-30, 50-69, how can I set tag in epw? (In wannier90, I can just use exclude_band tag)

Thank you.

Best regards,

Posted: **Tue Nov 01, 2016 5:17 pm**

Dear hanwooh,

As I said, you can use nbndskip 12 to exclude 1-12.

At the moment you cannot exclude 29-30, 50-69.

However this should not be very useful (except maybe in some very specific case).

You can skip the n first band and the m last band as well (just wannierized less than available nbnd from the nscf calculation).
Therefore you can narrow down the wannierization.

I cannot think of a useful case where you would remove band inside the Wannierization range except maybe with rare-earth and localized band inside the bandgap.

Cheers,

Samuel

Posted: **Wed Nov 02, 2016 4:13 am**

Dear Samuel,

Thank you for your advice.

I'll keep in my mind your advice when I do run wannier90.

Thank you again.

Best regards,

EPW Forum

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