[Pw_forum] LO-TO spliting in GaAs

[Stefano Baroni]

On Oct 30, 2008, at 6:55 PM, Shyam wrote:

> Hello all,
> I am trying to get the LO-TO splitting in GaAs. But I am a bit  
> confused about the pseudo potential to be used.  I have done  
> calculations using both the ultrasoft pseudopotential (USPP)  and  
> the normconserving (NCPP). The phonon DOS which I have got using  
> USPP is matching with the reported one and that I have got using  
> NCPP is not matching. On the other hand, NCPP is giving the values  
> of LO and TO modes closer to the experimental where as the values  
> obtained using USPP are more deviated from the reported one.
> Please help me.

How could we, without knowing anything of the way you have performed  
your calculations?
Please, do not forget to sign your corespondence to this mailinglist,  
including your current affiliation.

SB



---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
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