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

[lan haiping]

Thank you ,Stefano!
I have misinterpreted the meaning of effective mass.
When we talk about NFE states, does it mean that such
E-K dispersion should be held between 2 symmetry points, like from X-> Gamma
?

On Mon, Apr 28, 2008 at 1:40 AM, Stefano Baroni <baroni at sissa.it> wrote:

> 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
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> Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center - Trieste
> [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
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-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
lanhaiping at gmail.com, hplan at pku.edu.cn
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