elastic.finite difference.orthorombic structure

evgenii · Post by **evgenii** » Mon Aug 11, 2014 11:01 pm

Hi,

I need to compute elastic constants of orthorombic structure : C11, C22, C33, C44, C55, C66, C12, C13, C23

I use PAW and LDA+U(Abinit 7.8.1) to compute ground state of orthorombic structure.

As I understand that the strain perturbation is not implemented in PAW.

So I use finite difference calculation in such case.

As I understand that we can compute C11, C22, C33 from stress tensor(sigma).

But is it possible to obtain other components(C44, C55, C66 and etc)?

Please explain.
Thanks