[Pw_forum] Regarding electron phonon calculations

[Kondaiah Samudrala]

Dear all,

I am calculating the Tc value of monolayer TMDS using electron-phonon
dispersions as given in example03.

Indeed, I found all my phonon frequencies are positive (except  first low
acoustic mode at gamma point, which is -4 cm-1). I also observed that my
elph.inp_lambda.1 is as below

           0.000000      0.000000      0.000000    10     9
 -0.147906E-08  0.382782E-08  0.382782E-08  0.140575E-05  0.140575E-05
0.411996E-05
  0.454432E-05  0.454432E-05  0.718661E-05

So, Shall I considered the first value (i.e.  -0.147906E-08) as zero for
lambda.x calculations or need to more refine my parameters for structural
optimizations??? below I am giving my details

For structural optimizations :
    etot_conv_thr = 1.0D-10
    forc_conv_thr = 1.0D-8
    degauss=0.05,
    smearing='gauss',
    occupations='smearing',
    conv_thr =  1.0d-12
    Kpoints : 32 32 1
In this set up,  i found that the output stress is around 0.04.

For electron-phonon calculations
KPOINTS are 64 64 1 (in the case la2F=.true.)
KPOINTS are 32 32 1 (in normal SCF)
    etot_conv_thr = 1.0D-10
    forc_conv_thr = 1.0D-8
     tr2_ph=1.0d-16,
     electron_phonon='interpolated',
     el_ph_sigma=0.005,
     el_ph_nsigma=10,
     trans=.true.,
     ldisp=.true.
    nq1=8, nq2=8, nq3=1

Hope a positive reply and thanks in advance

with best regards
S. Appalakondaiah
Researcher
SAINT, SKKU
South Korea
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