[Pw_forum] Question about Example10

[lan haiping]

Dear Paolo,

I then test this result with ph.x code.
The born effetive charge tensors obtained are greatly consistent with
published results in Zhong et al (PRL.72.3618) , for O sites (-5.81,-2.57,-
2.57) , for Pb sites (3.92,3.92,3.92) (all are  diagonal elements of E-U
tensors).

I then recalculated with Berry Phase method, and still cannot find
satisfactory results for O sites. A typical resulted tensor is (-5.84, -1.90
,-1.98).
Would you please give some comments ?

regards,
h.p



On 1/14/07, Paolo Giannozzi <giannozz at nest.sns.it> wrote:
>
>
> On Jan 13, 2007, at 6:58 , lan haiping wrote:
>
> >  I have  a question about berry phase calculation for born effetive
> > charge implemented in espresso. [...] I could obtain  born
> > effective tensor of Pb site
> > about  3.9 -3.92 e whenever i increase ecutoffrho , conv_thr or use
> > denser
> > kmesh. But the born effective tensor of O sites , i.e . the three
> > diagonal
> > elements are not consistent with the result  of Zhong et al (PRL.
> > 72.3618).
> > The values i obtained are  -1.98 , -5.85, -1.90e  respectively for
> > 3 different
> > directions.
>
> did you try linear response? If you get the same result, that's it
> P.
> ---
> Paolo Giannozzi, Democritos and University of Udine, Italy
>
>
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-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
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