[Pw_forum] electron-phonon interaction error.
Y. L. Li
ylli at theory.issp.ac.cn
Thu Nov 22 15:40:10 CET 2012
Dear Lorenzo,
> > I think this is unnormal.
> Why do you think it is unnormal? In high-symmetry materials and q-points it
> is perfectly normal to have onyl a few non-zero terms.
I think the value of matrix element should not be so large. I also check elph.0.00000.XXX.XX files, which also have very large value or illogical output. For example, for G point, part results of elph.0.0000 0.00000 0.0000 file is as follows.
0.000000 0.000000 0.000000 10 18
-0.126332E-05 -0.620414E-06 -0.154679E-06 0.107608E-05 0.147451E-05 0.169464E-05
0.408894E-05 0.645471E-05 0.698396E-05 0.107719E-04 0.144215E-04 0.183331E-04
0.194042E-04 0.296271E-04 0.410801E-04 0.831798E-04 0.131738E-03 0.169451E-03
Gaussian Broadening: 0.005 Ry, ngauss= 0
DOS = 6.629818 states/spin/Ry/Unit Cell at Ef= 10.374777 eV
lambda( 1)=******** gamma=******** GHz
lambda( 2)=******** gamma=******** GHz
lambda( 3)=******** gamma=******** GHz
lambda( 4)= 0.4250 gamma= 31.34 GHz
lambda( 5)= 0.0505 gamma= 5.11 GHz
lambda( 6)= 0.0273 gamma= 3.16 GHz
lambda( 7)=601.8197 gamma=******** GHz
lambda( 8)=350.6821 gamma=******** GHz
.................
You can see that many star happen. Also I noticed that values of some dynamical matrix element were connected together as presented as below.
Dynamical Matrix in cartesian axes
q = ( -0.310971568 -0.136778208 0.258285840 )
------
0.00174672 10.51302809 (see here) 0.00037302-10.51496752 -0.00002975 10.51477879
(see here) 0.00037302-10.51496752 -0.00108098 10.51459634 -0.00012917-10.51442422
-0.00002975 10.51477879 (see here) -0.00012917-10.51442422 -0.00025486 10.51457255
1 3
-0.00246965 10.51720967 0.00068821-10.51300824 0.00012537 10.51051515
0.00049193-10.51388748 0.00159857 10.51472824 -0.00196467-10.51474139
0.00064832 10.51324607 0.00147879-10.51444247 0.00078773 10.51321004
1 4
10.51411329 0.00042246 -10.51421211 -0.00161006 10.51191958 -0.00028359
-10.51392554 0.00013895 10.51339735 0.00115788 -10.51875627 0.00071854
10.51353792 0.00004149 -10.51165045 -0.00113263 10.51466247 -0.00032748
1 5
-0.00105101 10.51151308 -0.00097114-10.51337506 -0.00087478 10.51823862
-0.00093486-10.51426146 0.00079562 10.51524911 0.00088042-10.51220062
-0.00008398 10.51493606 -0.00145129-10.51582557 -0.00120748 10.51479141
..............................
> >
> > For example, at G point, It is
> >
> > 5.000000000000000E-003 0.762532099281104 6.62981783474504
> What are these numbers?
This is contents of a2Fq2r.51-61 files
>
>Do Your phonon dispersion look ok in the first place?
The phonon spectrum obtained by using calculated *.dyn1, *.dyn2,.... files is reasonable.
> Did you actually compute the el-ph coupling and found it to be uncorrect?
Yes. I obtained elph.*** files. Many outputted gamma values in elph.**.**.** files are uncorrect.
Thanks a lot.
Best wishes,
Yanling
Institute of solid state physics, cas, China.
>
> Dear all,
>
> I calculate el-ph interaction using espresso-5.0.1 package. My input file is Ok, which is confirmed by Xcrysden code. I got a2fq2r.* file at each q point selected. I noticed that large dynamical matrix elements were obtained, while all elements are zero at some point. I think this is unnormal.
>
> For example, at G point, It is
>
> 5.000000000000000E-003 0.762532099281104 6.62981783474504
> 1
>
> Dynamical Matrix in cartesian axes
>
> q = ( 0.000000000 0.000000000 0.000000000 )
>
> 1 1
> 137.60553244 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 137.79644417 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 137.58884974 0.00000000
> 1 2
> 137.54385366 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 137.31507421 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 137.52874532 0.00000000
> 1 3
> 137.50539357 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 137.54339987 0.00000000 0.02295830 0.00000000
> 0.00000000 0.00000000 0.01311991 0.00000000 137.55061180 0.00000000
> 1 4
> 137.58193625 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 137.55989359 0.00000000 0.02824413 0.00000000
> 0.00000000 0.00000000 0.01505453 0.00000000 137.55171888 0.00000000
> 1 5
> 137.50539357 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 137.54339987 0.00000000 -0.02295830 0.00000000
> 0.00000000 0.00000000 -0.01311991 0.00000000 137.55061180 0.00000000
> ................
> ...............
>
> At second point calculated, it is
> 5.000000000000000E-003 0.762532099268857 6.62981783246344
> 2
>
> Dynamical Matrix in cartesian axes
>
> q = ( 0.000000000 0.000000000 0.258285840 )
>
> 1 1
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 1 2
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 1 3
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 1 4
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 1 5
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000
> .........................
> .........................
>
> DO you meet this case? Could you tell me the reason or how to correct it?
>
> Part parameters in fit.in file are
> &system
> ibrav= 0, celldm(1)=9.37471363, nat= 6, ntyp= 2,nbnd = 36,
> ecutwfc =50.0, ecutrho = 500, occupations='smearing',smearing='mp',
> degauss=0.04, la2F=.true.
> /
> &electrons
> conv_thr = 1.0d-11
> mixing_beta = 0.4
> /
> ................
> part parameters in ph.in file:
>
> .Electron-phonon coefficients for ss
> &inputph
> tr2_ph=1.0d-14,
> prefix='lll',
> alpha_mix(1)=0.4,
> fildvscf='**dv',
> outdir='./tmp/',
> fildyn='111.dyn',
> electron_phonon='interpolated',
> trans=.true.,
> ldisp=.true.
> nq1=4, nq2=4, nq3=4
> /
>
>
> Many thanks
>
> Yanling
>
> Institute of solid state physics, P.R. China.
>
>
> ------
> ISSP
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