[Wien] Spontaneous polarization of PbTiO3

[Lokanath Patra]

Dear Oleg,

I am attaching the structure files which I have used for the calculation. I
have used similar procedure as given for BaTiO3 tutorial (same parameters
for initialising and same k-point mesh for Berrypi. The calculated
polarisation for cubic phase is very low. So so spontaneous polarisation is
still very low as given in my previous mail. I am unable to trace my
mistakes.

Best regards
Lokanath

On Wed, May 2, 2018 at 7:25 PM, Oleg Rubel <rubelo at mcmaster.ca> wrote:

> Dear Lokanath,
>
> PbTiO3 was one of compounds used in the test of BerryPI (see Table 3 in
> http://olegrubel.mcmaster.ca/publications/2013/Ahmed_CPC_184_2013.pdf). I
> think you should also compute polarization in the cubic structure of PbTiO3
> even though they are deemed to have no polarization. If this does not help,
> I would suggest looking into the structure more carefully, tetragonal
> distortion, compare with experiment, etc.
>
>
> I hope it will help
> Oleg
>
> --
> Oleg Rubel (PhD, PEng)
> Department of Materials Science and Engineering
> McMaster University
> JHE 359, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada
> <https://maps.google.com/?q=359,+1280+Main+Street+West,+Hamilton,+Ontario+L8S+4L8,+Canada&entry=gmail&source=g>
> Email: rubelo at mcmaster.ca
> Tel: +1-905-525-9140, ext. 24094
> Web: http://olegrubel.mcmaster.ca
>
> On 2018-May-02 08:38, Lokanath Patra wrote:
>
>> Dear all,
>>
>> I am using Berry phase tutorial to calculate the polarization of PbTiO3.
>> I have followed the BaTiO3 tutorial. I have two structures, one is
>> tetragonal (non-centrosymmetric) and the second one is cubic
>> (centrosymmetric). I have calculated the (spontaneous) polarization
>> as 1.189769e-01 C/m2 (as the cubic system doesn't posses any polarization)
>> which is very low as the reported values are around 80 to 100 µC/cm2.
>> Please help me.
>>
>> Regards
>> Lokanath
>>
>> --
>> Lokanath Patra
>> Ph.D Scholar
>> Dept. of Physics
>> School of Applied and Basic Sciences
>> Central University of Tamil Nadu
>> Thiruvarur
>> Tamil Nadu - 610004
>> Ph no - +91-8675834507
>>
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-- 
Lokanath Patra
Ph.D Scholar
Dept. of Physics
School of Applied and Basic Sciences
Central University of Tamil Nadu
Thiruvarur
Tamil Nadu - 610004
Ph no - +91-8675834507

-- 

Central University of Tamil Nadu is in not responsible for the contents of 
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