On Mon, Jan 11, 2016 at 11:37 PM, Mostafa Youssef <[email protected]> wrote:
> > I also get a non-cubic dielectric tensor for cubic semiconductors when I > allow the computation of the nonanalytic terms by specifying a q-vector and > q is not equal 0. But I do not fully understand what is going on here. I > think (but not very sure) if you do not specify q then you actually > calculate the nonanalytic terms for q->0 > you actually calculate only the "analytic" terms for q=0. There are no nonanalytic terms if no direction for q is specified. > and then you recover the correct cubic tensor with zone center phonons > contribution. > > On the other hand calculating epsilon_0 by applying electric field and > relaxing the ions yields a reasonable cubic dielectric tensor. > > I hope somebody can help in clarifying this. > not sure I have clarified anything; I just added a check so that if someone tries to compute the phonon contribution to the the dielectric tensor with TO-LO splitting on, a warning message is printed. Paolo > > Mostafa Youssef > MIT > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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