I am calculating the el-ph coupling strength, lambda via the EPC method (scf-ph-q2r-matdyn) and the EPW method. My system is a semiconductor CsGeI3. In both these methods the lambda is printing as zero. I am attaching the inputs.
&CONTROL
calculation = 'scf'
etot_conv_thr = 5.0000000000d-08
forc_conv_thr = 1.0000000000d-08
outdir = './'
prefix = 'csgei3'
pseudo_dir = './'
tprnfor = .true.
tstress = .true.
verbosity = 'high'
/
&SYSTEM
degauss = 2.0000000000d-02
ecutrho = 400
ecutwfc = 100
ibrav = 0
nat = 5
nosym = .false.
input_dft = 'PBESOL'
la2F = .true.
ntyp = 3
occupations = 'smearing'
smearing = 'gaussian'
degauss = 0.05
/
&ELECTRONS
conv_thr = 1.0000000000d-09
electron_maxstep = 80
mixing_beta = 4.0000000000d-01
/
ATOMIC_SPECIES
Cs 132.9054519 Cs.upf
Ge 72.64 Ge.upf
I 126.90447 I.upf
ATOMIC_POSITIONS crystal
Cs 0.0000250000 0.0000250000 0.0000250000
Ge 0.4684260000 0.4684260000 0.4684260000
I 0.5042230000 0.5042230000 0.0111030000
I 0.0111030000 0.5042230000 0.5042230000
I 0.5042230000 0.0111030000 0.5042230000
K_POINTS automatic
6 6 6 0 0 0
CELL_PARAMETERS angstrom
6.0991431900 0.0000000000 0.0000000000
0.1638917687 6.0969408018 0.0000000000
0.1638917687 0.1595453990 6.0948529437
&inputph
tr2_ph = 1.0d-20,
prefix = 'csgei3',
fildvscf = 'csgei3.dvscf',
fildyn = 'csgei3.dyn',
outdir = './',
ldisp = .true.
nmix_ph=20
alpha_mix(1)=0.9
electron_phonon = 'interpolated',
el_ph_sigma = 0.001,
el_ph_nsigma = 10,
nq1 = 2, nq2 = 2, nq3 = 2,
trans=.true.
/
&input
fildyn='csgei3.dyn',
flfrc='csgei3.fc',
la2f = .true.
zasr = 'crystal'
loto_2d = .true.
/
&input
asr = 'simple',
flfrc = 'csgei3.fc',
flfrq = 'csgei3.freq',
la2F = .true.,
dos = .false.,
fldos = 'phonon.dos'
ndos = 50
/
251
0.000000 0.000000 0.000000 1
0.010000 0.010000 0.010000 1
0.020000 0.020000 0.020000 1
The output for the ph calculation is as such:
Mode symmetry, C_1 (1) point group:
freq ( 1- 1) = 5.1 [cm-1] --> A
freq ( 2- 2) = 10.6 [cm-1] --> A
freq ( 3- 3) = 18.0 [cm-1] --> A
freq ( 4- 4) = 20.4 [cm-1] --> A
freq ( 5- 5) = 25.9 [cm-1] --> A
freq ( 6- 6) = 27.5 [cm-1] --> A
freq ( 7- 7) = 35.5 [cm-1] --> A
freq ( 8- 8) = 41.3 [cm-1] --> A
freq ( 9- 9) = 49.3 [cm-1] --> A
freq ( 10- 10) = 52.9 [cm-1] --> A
freq ( 11- 11) = 62.0 [cm-1] --> A
freq ( 12- 12) = 77.4 [cm-1] --> A
freq ( 13- 13) = 108.6 [cm-1] --> A
freq ( 14- 14) = 153.8 [cm-1] --> A
freq ( 15- 15) = 156.0 [cm-1] --> A
electron-phonon interaction ...
Gaussian Broadening: 0.001 Ry, ngauss= 0
DOS = 0.000000 states/spin/Ry/Unit Cell at Ef= 3.886122 eV
lambda( 1)= 0.0000 gamma= 0.00 GHz
lambda( 2)= 0.0000 gamma= 0.00 GHz
lambda( 3)= 0.0000 gamma= 0.00 GHz
lambda( 4)= 0.0000 gamma= 0.00 GHz
lambda( 5)= 0.0000 gamma= 0.00 GHz
lambda( 6)= 0.0000 gamma= 0.00 GHz
lambda( 7)= 0.0000 gamma= 0.00 GHz
lambda( 8)= 0.0000 gamma= 0.00 GHz
lambda( 9)= 0.0000 gamma= 0.00 GHz
lambda( 10)= 0.0000 gamma= 0.00 GHz
lambda( 11)= 0.0000 gamma= 0.00 GHz
lambda( 12)= 0.0000 gamma= 0.00 GHz
lambda( 13)= 0.0000 gamma= 0.00 GHz
lambda( 14)= 0.0000 gamma= 0.00 GHz
lambda( 15)= 0.0000 gamma= 0.00 GHz
Gaussian Broadening: 0.002 Ry, ngauss= 0
DOS = 0.000000 states/spin/Ry/Unit Cell at Ef= 3.979661 eV
lambda( 1)= 0.0000 gamma= 0.00 GHz
lambda( 2)= 0.0000 gamma= 0.00 GHz
lambda( 3)= 0.0000 gamma= 0.00 GHz
lambda( 4)= 0.0000 gamma= 0.00 GHz
lambda( 5)= 0.0000 gamma= 0.00 GHz
lambda( 6)= 0.0000 gamma= 0.00 GHz
lambda( 7)= 0.0000 gamma= 0.00 GHz
lambda( 8)= 0.0000 gamma= 0.00 GHz
lambda( 9)= 0.0000 gamma= 0.00 GHz
lambda( 10)= 0.0000 gamma= 0.00 GHz
lambda( 11)= 0.0000 gamma= 0.00 GHz
lambda( 12)= 0.0000 gamma= 0.00 GHz
lambda( 13)= 0.0000 gamma= 0.00 GHz
lambda( 14)= 0.0000 gamma= 0.00 GHz
lambda( 15)= 0.0000 gamma= 0.00 GHz
el-ph coupling is zero
Moderator: stiwari