[Pw_forum] problem with polarization

[hania djani-ait aissa]

Dear all,
i am trying to calculate polarization in ferroelectric materials with Aurivillius structure (tetragonal and orthorombic), but i often get two anomalies: negative polarization and polarization close to the "quantum" polarization. as an example: P= -0.23 (mod 0.248) C/m2.
could someone explain me that? i'll be grateful.
 
Hania Djani
Phd student
centre for development of advanced technologies
Algiers, Algeria
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