[Wien] Spontaneous polarization with Berry phase method

[mostefa djermouni]

Dear Oleg Rubel,


I have calculated the spontaneous polarization for BiCoO3 in tetragonal structure, and then, 

I have got different results between [0 - 2] range and [-1 - +1] range.

Please I have some questions:

- What is the significance of negative values of total polarization ?
- Why the values of P_x and P_y is not  ~0 ?
- Is my calculation is true ?

Please find in attached files the BiCoO3.struct, BiCoO3.berrypi (for non-centrosymmery case) and  
BiCoO3.berrypi (for centrosymmery case).

NB: the spontaneous polarization of BiCoO3 in literature is: 179 uCm/


Thanks in advance. 


-------------------------------------------------------
Mostefa DJERMOUNI
Modeling and Simulation in Materials Science Laboratory
University of Sidi Bel-Abbes
22000 Sidi Bel-Abbes, Algeria
Tel: +213 795 626 105
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