[QE-users] Polarization

[Bruno Dandogbessi]

Dear All,

Season Greetings!

Please, I am running calculations of polarization using Berry phase
approach as implemented in quantum espresso for tetragonal phase of
PbTiO_3. The results look a little bit strange for me.
For unit cell, I am getting 0.94 C/m^2 of polarization whereas for super
cell the polarization is 0.098 C/m^2.

Please, Why such difference between unit cell & super cell?

Thanks be to You for any help as well as suggestions.

Cheers!
Bruno
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20200103/da49a41c/attachment.html>