:(, 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_______________________________________________ > > 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 pens?e - 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 > > > > > > > > > > > > > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum > > > > > > > -- > 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 pens?e - 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 > > > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- Hai-Ping Lan Department of Electronics , Peking University , Bejing, 100871 lanhaiping at gmail.com, hplan at pku.edu.cn -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20080505/7004ba40/attachment-0001.htm
