I agree that is probably an effect of the supercell size. How big is the supercell that you are using?<br><br>Cheers,<br>Sanda<br><br><div class="gmail_quote">On Fri, Sep 18, 2009 at 8:47 AM, Duy Le <span dir="ltr"><<a href="mailto:ttduyle@gmail.com">ttduyle@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">if the defect concentration is too hight, when you do vc-relax the lattice parameter will be re-optimized. In reality, the defect concentration is about zero.<br>
<br><div class="gmail_quote"><div><div></div><div class="h5">On Fri, Sep 18, 2009 at 8:43 AM, xirainbow <span dir="ltr"><<a href="mailto:nkxirainbow@gmail.com" target="_blank">nkxirainbow@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div></div><div class="h5">Dear:<br><br>When you calculate without vc-relax, you deal with a point defect.<br>
When you use vc-relax, you change the crystal parameters. That is to say, you deal with a new kind of crystal, not a point defect.<br>
It is just my own point of view ：）<div><div></div><div><br>
<div class="gmail_quote"><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td style="font-family: inherit; font-style: inherit; font-variant: inherit; font-weight: inherit; font-size: inherit; line-height: inherit; font-size-adjust: inherit; font-stretch: inherit;" valign="top">
<br><br>Ali Kazempour<br>
Physics department, Isfahan University of Technology<br>
84156 Isfahan, Iran. Tel-1: +98 311 391 3733<br>
Fax: +98 311 391 2376 Tel-2: +98 311 391 2375<br><br>--- On <b>Fri, 9/18/09, ali kazempour <i><<a href="mailto:kazempoor2000@yahoo.com" target="_blank">kazempoor2000@yahoo.com</a>></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">
<br>From: ali kazempour <<a href="mailto:kazempoor2000@yahoo.com" target="_blank">kazempoor2000@yahoo.com</a>><br>Subject: defect formation energy<br>To: <a href="mailto:forum@democritos.it" target="_blank">forum@democritos.it</a><br>
Date: Friday, September 18, 2009, 5:31 AM<br><br><div><table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td style="font-family: inherit; font-style: inherit; font-variant: inherit; font-weight: inherit; font-size: inherit; line-height: inherit; font-size-adjust: inherit; font-stretch: inherit;" valign="top">
<br>Hi<br>for study of point defect , i do relax calculation and obtain positive defect formation energy while by vc-relax i gain negative. ?<br>what is the difference between positive and negative formation energy? waht is the
physical reasons?<br>thanks a lot<br>Ali Kazempour<br>
Physics department, Isfahan University of Technology<br>
84156 Isfahan, Iran. Tel-1: +98 311 391 3733<br>
Fax: +98 311 391 2376 Tel-2: +98 311 391 2375</td></tr></tbody></table><br>
</div></blockquote></td></tr></tbody></table></blockquote></div><br><br clear="all"><br></div></div><font color="#888888">-- <br>____________________________________<br>Hui Wang<br>School of physics, Nankai University, Tianjin, China<br>
</font><br></div></div><div class="im">_______________________________________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org" target="_blank">Pw_forum@pwscf.org</a><br>
<a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
<br></div></blockquote></div><font color="#888888"><br><br clear="all"><br>-- <br>--------------------------------------------------<br>Duy Le<br>PhD Student<br>Department of Physics<br>University of Central Florida.<br>
</font><br>_______________________________________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
<a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
<br></blockquote></div><br>