<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt">Hi,<br> <br>The way you used to generate q-points is somewhat unusual, but seems to be correct.<br><br>Try also PlotPhon utility in your QE suite. <br><br>Bests,<br>Eyvaz.<br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> lucking-pine <songsong19840614@gmail.com><br><b><span style="font-weight: bold;">To:</span></b> PWSCF Forum <pw_forum@pwscf.org><br><b><span style="font-weight: bold;">Sent:</span></b> Sat, May 14, 2011 5:04:44 AM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [Pw_forum] why K-X point of phonon dispersion is wrong?<br></font><br>
<div>Dear Eyvaz Isaev:</div>
<div>Hi,Thanks for your help.I will read these books you <span id="result_box" class="short_text" lang="en"><span class="hps" title="点击可显示其他翻译">Recommended.</span></span></div>
<div><span class="short_text" lang="en"><span class="hps" title="点击可显示其他翻译">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?</span></span></div>
<div><span class="short_text" lang="en"><span class="hps" title="点击可显示其他翻译"></span></span> </div>
<div><span class="short_text" lang="en"><span class="hps" title="点击可显示其他翻译">Bests,</span></span></div>
<div><span class="short_text" lang="en"><span class="hps" title="点击可显示其他翻译">Pine.</span></span></div>
<div><span class="short_text" lang="en"><span class="hps" title="点击可显示其他翻译"> </span></span></div>
<div class="gmail_quote">2011/5/14 Eyvaz Isaev <span dir="ltr"><<a rel="nofollow" ymailto="mailto:eyvaz_isaev@yahoo.com" target="_blank" href="mailto:eyvaz_isaev@yahoo.com">eyvaz_isaev@yahoo.com</a>></span><br>
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<div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">Hi,<br><br>XCryDen gives you q-points coordinates with respect to basis vectors. <br>But X(1,1,0) and K(3/4,3/4,0) are in Cartesian and in units of 2*\pi/a. <br>
<br>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.<br>Or see a text book (H.Jones The Theory of Brillouin zones and electronic states in crystals, or J. Callaway Energy band Theory, or <br>
whatever you like) to find them in Cartesian.<br> <br><br>Bests,<br>Eyvaz. <br>
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<b><span style="font-weight: bold;">From:</span></b> lucking-pine <<a rel="nofollow" ymailto="mailto:songsong19840614@gmail.com" target="_blank" href="mailto:songsong19840614@gmail.com">songsong19840614@gmail.com</a>><br></div><b><span style="font-weight: bold;">To:</span></b> PWSCF Forum <<a rel="nofollow" ymailto="mailto:pw_forum@pwscf.org" target="_blank" href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a>><br>
<b><span style="font-weight: bold;">Sent:</span></b> Wed, May 11, 2011 5:34:10 AM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [Pw_forum] why K-X point of phonon dispersion is wrong?<br></font>
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<div>Dear Eyvaz Isaev:</div>
<div>Thank you for your advice.My k-point is chosen by Xcrysden.such as:</div>
<div>G 0.0000000000 0.0000000000 0.0000000000 <br>K -0.7500000000 -0.3750000000 -0.3750000000 <br>X -0.5000000000 0.0000000000 -0.5000000000 <br>G 0.0000000000 0.0000000000 0.0000000000 <br>
L - 0.5000000000 -0.5000000000 -0.5000000000 <br>X 0.0000000000 -0.5000000000 -0.5000000000 </div>
<div>W -0.2500000000 -0.5000000000 -0.7500000000 <br>L -0.5000000000 -0.5000000000 -0.5000000000<br><br>and I try to use your advice through using 3 type of attempt.</div>
<div>1.only chang K,Xpoint of K-G path to K(0.75,0.75,0), X point (1, 1, 0) </div>
<div>2.all k point multipy 2 times.</div>
<div> such as:</div>
<div>
<div>G 0.0000000000 0.0000000000 0.0000000000 <br>K -1.5000000000 -0.7500000000 -0.7500000000 <br>X -1.0000000000 0.0000000000 -1.0000000000 <br>G 0.0000000000 0.0000000000 0.0000000000 <br>
L - 1.0000000000 -1.0000000000 -1.0000000000 <br>X 0.0000000000 -1.0000000000 -1.0000000000 </div>
<div>W -0.5000000000 -1.0000000000 -1.5000000000 <br>L -1.0000000000 -1.0000000000 -1.0000000000<br><br>3.only K,Xpoint of K-G path multiply 2 times.</div>
<div> such as</div>
<div>
<div>G 0.0000000000 0.0000000000 0.0000000000 <br>K -1.5000000000 -0.7500000000 -0.7500000000 <br>X -1.0000000000 0.0000000000 -1.0000000000 <br>G 0.0000000000 0.0000000000 0.0000000000 <br>
L - 0.5000000000 -0.5000000000 -0.5000000000 <br>X 0.0000000000 -0.5000000000 -0.5000000000 </div>
<div>W -0.2500000000 -0.5000000000 -0.7500000000 <br>L -0.5000000000 -0.5000000000 -0.5000000000<br><br>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 ?</div>
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<div class="gmail_quote">2011/5/6 Eyvaz Isaev <span dir="ltr"><<a rel="nofollow" ymailto="mailto:eyvaz_isaev@yahoo.com" target="_blank" href="mailto:eyvaz_isaev@yahoo.com">eyvaz_isaev@yahoo.com</a>></span><br>
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<div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">Hi,<br><br>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.<br>
<br>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 <br>the X(1,0,0) point. Then from the X(1,0,0) to the Gamma (0,0,0) point.<br>
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) .<br><br>Please also provide your affiliation.<br><br>Bests,<br>
Eyvaz<br> <br>
<div>-------------------------------------------------------------------<br></div>Prof. Eyvaz Isaev, <br>Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden <br>Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <br>
<a rel="nofollow" ymailto="mailto:isaev@ifm.liu.se" target="_blank" href="mailto:isaev@ifm.liu.se">isaev@ifm.liu.se</a>, <a rel="nofollow" ymailto="mailto:eyvaz_isaev@yahoo.com" target="_blank" href="mailto:eyvaz_isaev@yahoo.com">eyvaz_isaev@yahoo.com</a>
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<b><span style="font-weight: bold;">From:</span></b> lucking-pine <<a rel="nofollow" ymailto="mailto:songsong19840614@gmail.com" target="_blank" href="mailto:songsong19840614@gmail.com">songsong19840614@gmail.com</a>><br><b><span style="font-weight: bold;">To:</span></b> <a rel="nofollow" ymailto="mailto:Pw_forum@pwscf.org" target="_blank" href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
<b><span style="font-weight: bold;">Sent:</span></b> Fri, May 6, 2011 2:50:16 PM<br><b><span style="font-weight: bold;">Subject:</span></b> [Pw_forum] why K-X point of phonon dispersion is wrong?<br></font>
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<div><br>
<p>My pwscf is used in calculating Si phonon dispersion.The trend of picture in </p>
<p>most special Symmetry is right.But the only K-X is wrong.I use Xcrysden to </p>
<p>get K-point.<br>I found most paper is dash line in 'K' point.So what is mean? Please anyone </p>
<p>could tell me! Thanks!<br>The attachment is my picture and reference paper.</p></div></div></div></div></div></div><br>_______________________________________________<br>Pw_forum mailing list<br><a rel="nofollow" ymailto="mailto:Pw_forum@pwscf.org" target="_blank" href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
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