Dear Eyvaz, Thank you very much,I will try these two factors.
max --- Eyvaz Isaev <eyvaz_isaev at yahoo.com> ?? > Dear Max, > > One can see that \lambda you got is quite small, > just > around zero. So, a reason might be numerical noise > for > such a kind small \lambda. \gamma depends also on > production of two delta functions which couples two > electronic states at the Fermi Surface and it > converges slowly. I suggest you should perform tests > with respect to number of k-points (more fine that > you > used), and higher cutoff energies. > > Bests, > Eyvaz. > P.S. Just today I have got \lambda for a metal, > around > 0.5, and everything went smoothly. > > --- ? ?? <chen_shao_hua197 at yahoo.com.tw> wrote: > > > Dear Eyvaz and forum's members, > > > > When I calculated the el-ph coupling constant > > \lambda > > of material.I find some negative value > > > > Electron-phonon coupling constant, lambda > > > > Broadening 0.0100 lambda 0.0008 dos_el > > 0.3719 > > Broadening 0.0200 lambda 0.0012 dos_el > > 0.3674 > > Broadening 0.0300 lambda 0.0021 dos_el > > 0.3565 > > Broadening 0.0400 lambda -0.0098 dos_el > > 0.3821 > > Broadening 0.0500 lambda -0.0303 dos_el > > 0.5231 > > Broadening 0.0600 lambda -0.0394 dos_el > > 0.7545 > > Broadening 0.0700 lambda -0.0408 dos_el > > 1.0409 > > Broadening 0.0800 lambda -0.0382 dos_el > > 1.3767 > > Broadening 0.0900 lambda -0.0333 dos_el > > 1.7603 > > Broadening 0.1000 lambda -0.0274 dos_el > > 2.1824 > > > > Also find some negative value in gam.line > > e.g. > > 24 0.0000 0.0000 0.0000 -0.0001 0.0000 > > -0.0001 ***** 0.0000 0.0000 > > > > But no negative frequency found in matdyn.freq > > > > I thought -\lambda comes from -\gamma (phonon > > linewidth), and -\gamma comes from -\omega > > (frequency) by its definitions. > > > > So I wonder why I got -\lambda and -\gamma (It > > should > > be >=0) > > even frequency \omega seems fine (no negative) ??? > > > > Should I just try check convergence of \gamma in > > dependent on cutoff energy and k-points sampling ? > > (from forum's "search archive", title " 3 > questions > > about elph file of Calculation of electron-phonon > > interaction coefficients" suggestions ) > > > > Thanks in advance > > > > max > > PHD candidate > > Physics department, National Taiwan > > University,Taiwan > > > > > > > > > ____________________________________________________________________________________________ > > > 2G??????Yahoo??????2.0??????????? > > http://tw.mg0.mail.yahoo.com/dc/landing > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum > > > > > ------------------------------------------------------------------- > Prof. Eyvaz Isaev, > Theoretical Physics Department, Moscow State > Institute of Steel & Alloys, Russia, > IFM, Linkoping University, Sweden > Condensed Matter Theory Group, Uppsala University, > Sweden > Eyvaz.Isaev at fysik.uu.se, eyvaz_isaev at yahoo.com > > > > ____________________________________________________________________________________ > Never miss a thing. Make Yahoo your home page. > http://www.yahoo.com/r/hs > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > ______________________________________________________________________________________________________ ?????????Yahoo!??????2.0????????????? http://tw.mg0.mail.yahoo.com/dc/landing
