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by searching google "non symmetric born effective charge" I found
the following reference to a pw_forum previous entry<br>
<a class="moz-txt-link-freetext" href="http://www.democritos.it/pipermail/pw_forum/2006-January/003511.html">http://www.democritos.it/pipermail/pw_forum/2006-January/003511.html</a><br>
that may be of interest.<br>
<br>
There is also a reference to a paper Cockayne-Burton PRB 62, 3735
(2000) on CaTiO3 that maybe is relevant to your case.<br>
<br>
stefano <br>
<br>
On 04/07/2011 09:54 AM, mohaddeseh abbasnejad wrote:
<blockquote
cite="mid:BANLkTinWn9K1Zoqyb2aWuDXWdcEJxgw-hA@mail.gmail.com"
type="cite">
<pre wrap="">Thanks for your reply.
I am working on one of the orthorhombic structures of TiO2.
and it is the first time I have faced this problem.
Yours,
M. Abbasnejad
University of Tehran
On Thu, Apr 7, 2011 at 12:04 PM, Stefano de Gironcoli <a class="moz-txt-link-rfc2396E" href="mailto:degironc@sissa.it"><degironc@sissa.it></a>wrote:
</pre>
<blockquote type="cite">
<pre wrap=""> what is your system ?
born effective charges are not necessarily hermitian although very often
they are.
stefano
On 04/07/2011 09:28 AM, mohaddeseh abbasnejad wrote:
Dear all,
Trying to calculate the born effective charges of my case, the obtained
diagonalized principal values of effective charge tensor have imaginary
part.
The system has been relaxed carefully using Perdew-Zunger ultrasoft
psuedopotentilas by ecutoff=50 (55) Ry, and performing the BZ integration in
a 6×6×6 grid with 27 reduced
number of k points in the irreducible edge of the 1st BZ.
What may cause the problem?
Thanks for any comment.
Yours,
M. Abbasnejad
University of Tehran
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