Dear EPW Developers and Users,
Recently, I am calculating the electron-phonon coupling in the 2D MoS2. Following the posts in the EPW forum, I have prepared the input file of epw and calculate the electron-phonon coupling using the EPW-4.1. However, the calculated value is far too large, just like this:
73.5736320 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000
Integrated el-ph coupling
295.9530319 300.2090991 306.0841297 312.8515565 319.3059782 324.5751299 328.3089847 330.5235911 331.4169220 331.2457465
Phonon smearing (meV)
0.2000000 0.2500000 0.3000000 0.3500000 0.4000000 0.4500000 0.5000000 0.5500000 0.6000000 0.6500000
Electron smearing (eV) 0.0200000
Fermi window (eV) 3.0000000
Summed el-ph coupling 289.8528171
My input file of epw.in is:
&inputepw
prefix=‘mos2’,
amass(1)=95.94,
amass(2)=32.085,
outdir = ‘./’
ep_coupling = .true.
elph = .true.
kmaps = .false.
epbwrite = .false.
epbread = .false.
etf_mem = .false.
epwwrite = .false.
epwread = .false.
nbndsub = 22
nbndskip = 0
wannierize = .true.
num_iter = 500
!dis_win_max = 50
!dis_win_min = -10
!dis_froz_min= -10
!dis_froz_max= 30
proj(1) = ‘Mo:d’
proj(2) = ‘S:sp2’
system_2d = .true.
iverbosity = 2
!elinterp = .true.
!phinterp = .true.
!tshuffle2 = .true.
!tphases = .false.
elecselfen = .true.
phonselfen = .true.
a2f = .true.
parallel_k = .true.
parallel_q = .false.
fsthick = 3! eV
eptemp = 300 ! K
degaussw = 0.02 ! eV
nsmear = 1
delta_smear =0.02
degaussq = 0.2 ! meV
nqstep = 500
efermi_read = .true.
fermi_energy =5.3584 !eV
dvscf_dir = ‘../phonon/save’
! filqf = ‘phon_band.qpt’
nk1 = 16
nk2 = 16
nk3 = 1
nq1 = 8
nq2 = 8
nq3 = 1
nkf1 = 64
nkf2 = 64
nkf3 = 1
nqf1 = 32
nqf2 = 32
nqf3 = 1
/
10 cartesian
…
So what is the potential reason for such large electron-phonon coupling strength and how can I tune the parameters. Any suggestions?
Best,
Amos