[Pw_forum] [OT] How to identify NFE states ?

[Stefano Baroni]

The higher the energy, the lower the effect of the pseudopotential, so  
high-energy states are expected to be more free-electron like than low- 
lying ones. I am afraid that the very ocncept of "effective mass" is  
not very meaningful for these states. However, I would expect  
(although I have never verified) that for high-lying states the  
derivative of the band energy with respect to the wavenumber be linear  
with respect to the wavenumber, with the coefficient given by the  
inverse of the free-electron mass. SB

On Apr 27, 2008, at 8:27 AM, lan haiping wrote:

> Dear All,
>
>  I am wondering about the nearly free electron states . To identify  
> such states,
> does it mean that its effective mass is very close to free  
> electron ,And we can identify
> it from bands' dispersion ?
>
>  Bests
> H.P
>
> -- 
> Hai-Ping Lan
> Department of Electronics ,
> Peking University , Bejing, 100871
> lanhaiping at gmail.com, hplan at pku.edu.cn  
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
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