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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20080427/2806c094/attachment.htm
