The ABINIT Users Mailing List ( CLOSED )

[Xifan Wu <wuxifan@physics.rutgers.edu>]

Hi Julie,

The clamped-ion tensor is the piezoelectric calculated only from the
electrons (wavefunctions), the relaxed-ion tensor including the ions'
response. The former can be measured in experiment with high-frequency
where the ions keep rigid, the latter is measured in experiment with
low frequency limit, where the ions can relax. Usually, the latter is
more often reported in the literatures.

Xifan


On Fri, 6 Mar 2009, Julie Smart wrote:

> Dear Abinit users,
>
> I have a question on calculating the dilectric tensor in ABINIT. In the response function calculation, in lesson 
> "trf1-5.in", we have calculated the dielectric tensor for AlAs. Also, "Electronic dielectric 
> tensor" and "Relaxed ion dielctric tensor" has been calculated in "tnlo-2".in and ... .
>
> I want to know what the difference between these dielectric tensors is. If the dielectric tensor calculated 
> from response function to homogeneous electric field is the "Relaxed ion dielctric tensor", why 
> do their values differ in "tnlo-2.in" and "trf1-5.in"?
>
> Regards,
> Julie