[Pw_forum] Perturbation in electronic field

[yumin qian]

>
> 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://lists.quantum-espresso.org/pipermail/users/attachments/20081010/731d76ca/attachment.html>