Hi, The way you used to generate q-points is somewhat unusual, but seems to be correct.
Try also PlotPhon utility in your QE suite. Bests, Eyvaz. ________________________________ From: lucking-pine <[email protected]> To: PWSCF Forum <pw_forum at pwscf.org> Sent: Sat, May 14, 2011 5:04:44 AM Subject: Re: [Pw_forum] why K-X point of phonon dispersion is wrong? 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/20110515/b3d5292e/attachment.htm
