Dear Mostafa Thanks a lot
On 5/12/15, Mostafa Youssef <[email protected]> wrote: > Hi Mojtaba, > > Polarization is a vector, so negative or positive just indicate its > direction. So no worries about negative polarization. But in periodic > boundary conditions you may still need to add (subtract) multiples of the > polarization quantum in order to get the "reasonable" value of the > spontaneous polarization of the material. > > A favorite of mine which go over some of these difficulties is this paper: > > http://journals.aps.org/prb/abstract/10.1103/PhysRevB.71.014113 > > > Mostafa Youssef > MIT > > > _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
