Dear Eyvaz Isaev: Hi,Thanks for your help.I will read these books you Recommended. And I want to ask that I use these k-points into <band.input>,and then the <band.output>will auto-transform the k-point into Cartesian and units of 2*\pi/a,and I use these output k-point in <matdyn.input>.I always get k-point in this way.Is there something wrong?
Bests, Pine. 2011/5/14 Eyvaz Isaev <eyvaz_isaev at yahoo.com> > Hi, > > XCryDen gives you q-points coordinates with respect to basis vectors. > But X(1,1,0) and K(3/4,3/4,0) are in Cartesian and in units of 2*\pi/a. > > If I am not wrong, matdyn.x uses (at least, always I used) q-points in > Cartesian, so, you have to transform these points to Cartesian. > Or see a text book (H.Jones The Theory of Brillouin zones and electronic > states in crystals, or J. Callaway Energy band Theory, or > whatever you like) to find them in Cartesian. > > > Bests, > Eyvaz. > > ------------------------------ > *From:* lucking-pine <songsong19840614 at gmail.com> > *To:* PWSCF Forum <pw_forum at pwscf.org> > *Sent:* Wed, May 11, 2011 5:34:10 AM > *Subject:* Re: [Pw_forum] why K-X point of phonon dispersion is wrong? > > Dear Eyvaz Isaev: > Thank you for your advice.My k-point is chosen by Xcrysden.such as: > G 0.0000000000 0.0000000000 0.0000000000 > K -0.7500000000 -0.3750000000 -0.3750000000 > X -0.5000000000 0.0000000000 -0.5000000000 > G 0.0000000000 0.0000000000 0.0000000000 > L - 0.5000000000 -0.5000000000 -0.5000000000 > X 0.0000000000 -0.5000000000 -0.5000000000 > W -0.2500000000 -0.5000000000 -0.7500000000 > L -0.5000000000 -0.5000000000 -0.5000000000 > > and I try to use your advice through using 3 type of attempt. > 1.only chang K,Xpoint of K-G path to K(0.75,0.75,0), X point (1, 1, 0) > 2.all k point multipy 2 times. > such as: > > G 0.0000000000 0.0000000000 0.0000000000 > K -1.5000000000 -0.7500000000 -0.7500000000 > X -1.0000000000 0.0000000000 -1.0000000000 > G 0.0000000000 0.0000000000 0.0000000000 > L - 1.0000000000 -1.0000000000 -1.0000000000 > X 0.0000000000 -1.0000000000 -1.0000000000 > W -0.5000000000 -1.0000000000 -1.5000000000 > L -1.0000000000 -1.0000000000 -1.0000000000 > > 3.only K,Xpoint of K-G path multiply 2 times. > such as > > G 0.0000000000 0.0000000000 0.0000000000 > K -1.5000000000 -0.7500000000 -0.7500000000 > X -1.0000000000 0.0000000000 -1.0000000000 > G 0.0000000000 0.0000000000 0.0000000000 > L - 0.5000000000 -0.5000000000 -0.5000000000 > X 0.0000000000 -0.5000000000 -0.5000000000 > W -0.2500000000 -0.5000000000 -0.7500000000 > L -0.5000000000 -0.5000000000 -0.5000000000 > > However,all this attempts yield wrong picture. So,this must be something I > didn't understand correctly.Would you tell me where is my fault ? > 2011/5/6 Eyvaz Isaev <eyvaz_isaev at yahoo.com> > >> Hi, >> >> First of all I would recommend the use of PlotPhon utility to plot phonon >> dispersion relations. For this one you have to have calculated interatomic >> force constants matrix (*.fc) file. >> >> Regarding your particular question: you should choose K(0.75,0.75,0), then >> from the K point go to the X point (1, 1, 0) which is equivalent to >> the X(1,0,0) point. Then from the X(1,0,0) to the Gamma (0,0,0) point. >> Dashed line just means that we can continue in this direction to match >> phonons at the X point (i.e. it is an intermediate point from the Gamma to >> the X point) . >> >> Please also provide your affiliation. >> >> Bests, >> Eyvaz >> >> ------------------------------------------------------------------- >> Prof. Eyvaz Isaev, >> Department of Physics, Chemistry, and Biology (IFM), Linkoping University, >> Sweden >> Theoretical Physics Department, Moscow State Institute of Steel & Alloys, >> Russia, >> isaev at ifm.liu.se, eyvaz_isaev at yahoo.com >> >> >> ------------------------------ >> *From:* lucking-pine <songsong19840614 at gmail.com> >> *To:* Pw_forum at pwscf.org >> *Sent:* Fri, May 6, 2011 2:50:16 PM >> *Subject:* [Pw_forum] why K-X point of phonon dispersion is wrong? >> >> My pwscf is used in calculating Si phonon dispersion.The trend of picture >> in >> >> most special Symmetry is right.But the only K-X is wrong.I use Xcrysden to >> >> >> get K-point. >> I found most paper is dash line in 'K' point.So what is mean? Please >> anyone >> >> could tell me! Thanks! >> The attachment is my picture and reference paper. >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> >> > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110514/9e4da2fc/attachment.htm
