Re: [Pw_forum] Negative Polarization !!!
Dear Mostafa Thanks a lot On 5/12/15, Mostafa Youssef 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 Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Negative Polarization !!!
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 Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
[Pw_forum] Negative Polarization !!!
Dear All If we have a negative total polarization (by nscf+lberry),has it meaning? This happens, for example, in strain study of tetragonal perovskites. if it has meaning, what does it mean, physically? I have some problem with negative polarization Regards Mojtaba Mirseraji Ph.D. Candidate Theoretical Condensed Matter Physics Arak University I.R.IRAN ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum