Piezoelectric Tensor Units?  [SOLVED]

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aliwho
Posts: 8
Joined: Mon Oct 31, 2016 3:56 am

Piezoelectric Tensor Units?

Post by aliwho » Wed May 16, 2018 7:32 pm

Hello,

I'm having some trouble understanding the units Anaddb writes out the piezoelectric tensor with.
The piezoelectric tensor should have units of m/V (usually on the order of pm/V), but Anaddb claims the units it's using are C/m^2, which isn't equivalent to m/V.
I'm further confused by this recent thread https://forum.abinit.org/viewtopic.php?f=10&t=3822 in which the ABINIT user has output of pC/N, which is equivalent to m/V!

Can anyone shed some light on this?
Thanks,
-Ali

ebousquet
Posts: 469
Joined: Tue Apr 19, 2011 11:13 am
Location: University of Liege, Belgium

Re: Piezoelectric Tensor Units?  [SOLVED]

Post by ebousquet » Sat May 19, 2018 1:44 pm

Dear Ali,
You have several definitions of the piezoelectric tensor (e, d, etc ) with different units and you can select which one you want through the anaddb flag piezoflag (https://docs.abinit.org/variables/anaddb/#piezoflag).
You can also find some details in the former Phys. Rev. B 72, 035105 (2005) paper of Don Hamann who implemented this response in Abinit (https://journals.aps.org/prb/abstract/10.1103/PhysRevB.72.035105).
Best wishes,
Eric

aliwho
Posts: 8
Joined: Mon Oct 31, 2016 3:56 am

Re: Piezoelectric Tensor Units?

Post by aliwho » Sun May 20, 2018 9:22 pm

ebousquet wrote:Dear Ali,
You have several definitions of the piezoelectric tensor (e, d, etc ) with different units and you can select which one you want through the anaddb flag piezoflag (https://docs.abinit.org/variables/anaddb/#piezoflag).
You can also find some details in the former Phys. Rev. B 72, 035105 (2005) paper of Don Hamann who implemented this response in Abinit (https://journals.aps.org/prb/abstract/10.1103/PhysRevB.72.035105).
Best wishes,
Eric

Thank you for those references, they helped clear things up a lot!

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