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

[Stefano Baroni]

sorry, but this time I do not understand what you mean ...
S>

On Apr 30, 2008, at 11:56 AM, lan haiping wrote:

> 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
>> lanhaiping at gmail.com, hplan at pku.edu.cn  
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>
>
>
> ---
> Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
> Trieste
> [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
>
> La morale est une logique de l'action comme la logique est une  
> morale de la pensée - Jean Piaget
>
> Please, if possible, don't  send me MS Word or PowerPoint attachments
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>
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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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> Pw_forum at pwscf.org
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

La morale est une logique de l'action comme la logique est une morale  
de la pensée - Jean Piaget

Please, if possible, don't  send me MS Word or PowerPoint attachments
Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html





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