Electron-Phonon coupling matrix for conduction bands

[Patrick_1396]

Hi all,

I am trying to calculate the electron-phonon coupling matrix elements for SiC at the conduction band minimum, however with "prtgkk = =.true." the ouptu file only contains the el-ph matrix elements for the 4 valence bands.

I have been trying to extend the what is shown in Exercise 2 of Hands-on Session (Mon.3)
from the 2023 Virtual School on Many-Body Calculations using EPW and BerkeleyGW.


In case they can help,
My nscf.in file is

---------------------------------------------------------------------------
&control
calculation = 'nscf'
prefix = 'sic'
pseudo_dir = '../'
outdir = './'
/
&system
ibrav = 2
celldm(1) = 8.237
nat = 2
ntyp = 2
ecutwfc = 30.0
nbnd = 8
/
&electrons
diagonalization = 'david'
mixing_beta = 0.7
conv_thr = 1.0d-10
/
ATOMIC_SPECIES
Si 28.0855 Si.pz-vbc.UPF
C 12.01078 C.UPF
ATOMIC_POSITIONS alat
Si 0.00 0.00 0.00
C 0.25 0.25 0.25
K_POINTS crystal
216
0.00000000 0.00000000 0.00000000 4.629630e-03
0.00000000 0.00000000 0.16666667 4.629630e-03
0.00000000 0.00000000 0.33333333 4.629630e-03
...
---------------------------------------------------------------------------

And my epw.in file
---------------------------------------------------------------------------
&inputepw
prefix = 'sic'
amass(1) = 28.0855
amass(2) = 12.0107
outdir = './'
dvscf_dir = '../phonon/save'

elph = .true.
epwwrite = .true.
epwread = .false.
lpolar = .true.
vme = 'dipole'

wannierize = .true.
nbndsub = 4
num_iter = 300
proj(1) = 'Si:sp3'

prtgkk = .true.

filqf = 'path2.dat'
filkf = 'v_min.dat'

nk1 = 6
nk2 = 6
nk3 = 6
nq1 = 3
nq2 = 3
nq3 = 3
/
---------------------------------------------------------------------------

Cheers,
Patrick

[stiwari]

Hi,

This is expected because you have nbndsub=4 which means you only have four bands after the Wannierization step (proj(1) ='Si:sp3' =4 bands). To include more bands you have to increase nbndsub (include proj for C atoms too).

Best regards,
Sabya.