thanks for your reply 2008/10/10 Stefano Baroni <baroni at sissa.it>
> > On Oct 10, 2008, at 3:58 AM, yumin qian wrote: > > 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 ). > > > please, take the time to have a glance at: > S. Baroni, S. de Gironcoli, A. Dal Corso, and P. Giannozzi, Phonons and > related crystal properties from density-functional perturbation theory, Rev. > Mod. Phys. 73, 515 (2001). > > > > >> 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, > > > third, DFPT (restricted to the linear, or low-order) regime > > My question is in PWSCF how the electronic field is added , > > > through either of the first two methods. the third is implemented in PHONON > > and whether the method can be used in metal system ? > > > homogeneous electric fields in a metal? for that a computer code is not > enough. One should modify Maxwell's equations! > > SB > > --- > Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste > http://www.sissa.it/~baroni / [+39] 040 3787 406 (tel) -528 (fax) / > stefanobaroni (skype) > > La morale est une logique de l'action comme la logique est une morale de > la pens?e - Jean Piaget > > Please, if possible, don't send me MS Word or PowerPoint attachments > Why? See: http://www.gnu.org/philosophy/no-word-attachments.html > > > > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- 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/20081010/6d041853/attachment-0001.htm
