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[<g930102@ccit.edu.tw>]

The GW code is only valid for FCC lattice now?

Valerio Olevano <valerio.olevano@polytechnique.fr>
Dr. Valerio Olevano wrote:

>Yes you are right. the constant 7.44 is for the fcc cell. for other 
>cells you should take into account the different shape giving 
>different results when integrated.
>Please consider that the important factor given by the volume cell
>is taken into account in that term, so changing symmetry you are
>wrong only in that "shape prefactor".

Are you definitely to said that the GW code is only valid for FCC
lattice now? If we try to study other than FCC cell(for example, HCP
cell), and didn't change the "shape prefactor", then we will get the
wrong results.
If I am not misunderstand your meaning, that will explain what I am
wondering why the GWA-ABINIT away from DFTGWA in GaN(wurtzite). 
And what's the "shape prefactor" of wurtzite lattice? Could you list
some useful "shape prefactor"?
Thanks in advance!


>To solve the problem you can calculate the prefactor by yourself
>and change the code, recompile everytime you change symmetry, 
>or otherwise become a developper and give the correction to
>this bug. There is something in the code (read in the header of the
> KSS file)
>a variable giving the space group. In the point of the code where 
>the constant 7.44 is used the program should be changed according to
> the space group. 

Could you give a more advise how to calculate the prefactor by 
ourself?

Best regards,

Lu Fu-Fa   Sep/12/2002
=======================================================
Lu Fu-Fa, Doctoral Student, E-mail: g930102@ccit.edu.tw
Semiconductors Lab., Dept. of Applied Physics
Chung Cheng Institute of Technology (CCIT), TW
=======================================================

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