EPW Forum

Dear all,

I'm trying to calculate the electron phonon matrix elements of diamond at Gamma qpoint for all 8 electronic bands (4 valence and 4 conduction bands) that I'm using in my scf and nscf calculations. But when I set "prtgkk = .true.", the EPW code prints out only the el-ph matrix elements for the 3 branches of conduction band (I guess) as follows:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
iq = 1 coord.: 0.0000000 0.0000000 0.0000000
ik = 1 coord.: 0.0166666 -0.0499998 0.0166666
ibnd jbnd imode enk[eV] enk+q[eV] omega(q)[meV] |g|[meV]
------------------------------------------------------------------------------
2 2 1 12.5403 12.5403 0.0000031684 0.9039135138E+03
2 2 2 12.5403 12.5403 0.0000016810 0.9039135138E+03
2 2 3 12.5403 12.5403 0.0000032518 0.9039135138E+03
2 2 4 12.5403 12.5403 157.8433358187 0.4325595784E+03
2 2 5 12.5403 12.5403 157.8433358187 0.4325595784E+03
2 2 6 12.5403 12.5403 157.8433358187 0.4325595784E+03
2 3 1 12.5403 12.9230 0.0000031684 0.4354858171E+04
2 3 2 12.5403 12.9230 0.0000016810 0.4354858171E+04
2 3 3 12.5403 12.9230 0.0000032518 0.4354858171E+04
2 3 4 12.5403 12.9230 157.8433358187 0.2381222365E+03
2 3 5 12.5403 12.9230 157.8433358187 0.2381222365E+03
2 3 6 12.5403 12.9230 157.8433358187 0.2381222365E+03
2 4 1 12.5403 13.0388 0.0000031684 0.4362771725E+04
2 4 2 12.5403 13.0388 0.0000016810 0.4362771725E+04
2 4 3 12.5403 13.0388 0.0000032518 0.4362771725E+04
2 4 4 12.5403 13.0388 157.8433358187 0.2249035642E+03
2 4 5 12.5403 13.0388 157.8433358187 0.2249035642E+03
2 4 6 12.5403 13.0388 157.8433358187 0.2249035642E+03
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

However I need those elements for the cases where iband and jband run over (1,2,3,4) and (5,6,7,8) for the valence and conduction bands, respectively. Does anyone know who I can force EPW code to calculates and prints all the elements?

Thanks in advance.

Best,
Reza Vatan,
Electrical Engineering Department,
Arizona State University

Dear Reza Vatan:

Could you show me your epw.in?

Sincerely,

H. Lee

Hi H. Lee,

I know I'm not the original poster but I ham having a similar problem and couldn't find an answer. I am trying to calculate the electron-phonon coupling matrix elements for the first conduction band of SiC however I am only getting the coupling elements for the valence bands and I am not sure how to proceed.

Here's the input nscf.in that is run immediately before epw.

-----------------------------------------------------------------------------
&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 the input for epw.x.
-----------------------------------------------------------------------------
&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
/
-----------------------------------------------------------------------------

Sorry if this question has been answered elsewhere.
Cheers,
Patrick