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

[lan haiping]

:(, i think i have misunderstood the states' identification.
I thought  we could just figure out states like NFEs from bands structure,
and NFEs should have a similar energy dispersion of free electron between
different high symmetry points. Of course, we should also take the fold-up
into account for different  BZs.
After digging out some papers, i find we should judge state not just from
bands calculation, but also consider the shape of wavefunction.
I am really sorry for my poor expression and some misunderstangding,  Thanks
for your kindly reply and help.
Best
On Mon, May 5, 2008 at 4:03 AM, Stefano Baroni <baroni at sissa.it> wrote:

> 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
> > Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html
> >
> >
> >
> >
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> --
> Hai-Ping Lan
> Department of Electronics ,
> Peking University , Bejing, 100871
> lanhaiping at gmail.com, hplan at pku.edu.cn_______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>
> ---
> 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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-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
lanhaiping at gmail.com, hplan at pku.edu.cn
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