[Wien] Tr : Spontaneous polarization with Berry phase method

[Oleg Rubel]

Dear Mostefa,

For a long time we wanted to enable spin polarization in BerryPI. Maybe 
it is the right time to look at it.

> How can I calculate spontaneous polarization ? whith "LSDA+U and
> antiferromagnetic state (AFM-C)" or "LSDA and Non-Mgnetic state (NM)".

AFM-C will require a larger cell (2x2x2), so at that point I would stay 
with a single cell. I am trying LSDA+U for your structure and will let 
you know how to proceed.

Thank you
Oleg