<br> Dear Eyvaz, <br><br> Thanks a lot for your helpful reply. <br><br>> Z* and \epsilon, therefore, LO-TO splitting are for semiconductors/insulators. <br>> As you know, all valence bands are occupied, and conductivity bands are empty. Thus,<br>
> you can omit the smearing keyword to let pw.x know that you deal with a semiconductor.<br><br>I agree with you. <br>However, in practice, sometime smearing keyword needs to be used for a complicated<br>semiconductor or insulator in order get a faster scf convergence. And hence, <br>
it is better to identify a system is non-metal or metal by its band-gap instead of smearing <br>keyword. In particular, phonon code in QE complain a lot if the system is a spin-polarized insulator. <br>For example, "fixed occupations and lsda need tot_magnetization", <br>
"The phonon code with constrained magnetization is not yet available", <br> " IF (epsil.AND.lgauss) & CALL errore ('phq_readin', 'no elec. field with metals', 1)", etc. etc.<br>Atleast for the last error, I guess, it is better if we write, <br>
" IF (epsil.AND.gap_zero) & CALL errore ('phq_readin', 'no elec. field with metals', 1)"<br>
in place of the current existing statement. Then it will give a chance to compute \epsil also for <br>an insulating system which uses "smearing" keyword just for faster convergence.<br><br>> See example06<br>
<br>For magnetic insulator, is there any further example which shows <br>a phonon-dispersion with LO-TO splitting ? <br><br> > P.S. So, they are not related with postprocessing<br><br>I meant, postprocessing after ph.x.<br>
I thought, q2r.x and matdyn.x, plotband.x as post-processing of phonon code (ph.x) . <br><br><br>Thanking you and with my best regards, <br><br>Srijan Kumar <br>R&D Assistant <br>JNCASR<br>Bangalore 560064 <br> <br><div class="gmail_quote">
On Mon, Mar 14, 2011 at 1:54 PM, Eyvaz Isaev <span dir="ltr"><<a href="mailto:eyvaz_isaev@yahoo.com" target="_blank">eyvaz_isaev@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">Dear Srijan,<br><br>Z* and \epsilon, therefore, LO-TO splitting are for semiconductors/insulators. <br>As you know, all valence bands are occupied, and conductivity bands are empty. Thus,<br>
you can omit the smearing keyword to let pw.x know that you deal with a semiconductor.<br>Then you will got dyn1-file with Z* and \epsion, q2r.x and matdyn.x will take care about these <br>parameters and LO-TO splitting.<br>
<br>Having IFC (*.fc) file you can edit Z* and \epsilon.<br><br>See example06 and /Doc/PH.txt. <br><div> <br>Best regards,<br>Eyvaz.<br></div>P.S. So, they are not related with postprocessing<br>
</div></div></blockquote></div><br>