> > There is one problem I am not clear about DFPT in external electronmagnetic > field. How to switch on the external field since the field will distroy the > translational symmetry(periodic boundary condition ).
> There a two way right now : one is add a dipole layer in vaccum layers , > this method can only be used in slab calculation > the other is to add a periodic field and at the end make the periodic to > infinite (long wave appriximation). Vanderbilt also made a proposal using > the Berry phase approach, My question is in PWSCF how the electronic field is added , and whether the method can be used in metal system ? thank you -- Sincerely Y. M. Qian Lab.of Condensed Matter Theory and Materials Computation Institute of Physics Chinese Academy of Sciences Tel: + 8610 8264 9147 E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com> P.O.Box 603 Beijing 100190 China -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20081010/731d76ca/attachment-0001.htm
