[Pw_forum] questions on lattice dynamical principle
degironc at sissa.it
Wed Nov 22 16:59:05 CET 2006
good questions... why don't you ask the authors ?
> Dear all:
> I have read the paper titled ¡°Theory of systematic absence of
> NaCl-type (¦Â-Sn-type) high pressure phases in covalent (ionic)
> semiconductors¡± (Phys Rev Lett. *82*, 767, 1999). The phonon behaviors
> are dominated by the competition between the attractive electrostatic
> Madelung energy ¨CZ^2 /R (where Z is the excess charge within the
> atomic sphere) and the repulsive short-range energy.I can not
> understand well the formula of the force constant given in the last
> part of page 769. I thought to present the formula here.
> Unfortunately, I can not add it in my email text. I am very sorry for
> How does it come from? Does it apply to all the systems or just apply
> to some specific system? The values of A and ¦Ë are determined by what
> The authors claimed that the transverse acoustic mode at X point
> lowers the repulsive energy and raises the Madelung energy, but why?
> I have pondered hardly and consulted with others. But I have reached
> no conclusion.
> Any reply will be appreciated!
> With all my best regards!
> Yours sincerely
> Jingyun Zhang
> K a p p a \ A N D 1 \ R e e b o k È« ³¤ ³¡ 9 9 Ôª
> ÄÍ ¿Ë \ °¢ µÏ \ Àî Äþ ¡ Ëù ÓÐ ÔË ¶¯ µ¥ Æ· 1 9 9 Ôª ·â ¶¥ , ÏÞ Ê± ÇÀ ¹º
> À² !
More information about the users