[Pw_forum] bandgap of germanium
giannozz at nest.sns.it
Mon Aug 2 18:01:22 CEST 2004
On Saturday 31 July 2004 11:04, Bachir Bouhafs wrote:
> [...] I think that you have calculated your band structure at the
> experimental lattice parameter [...] which is greater than the LDA
> value. Which means, that you have applied a negative pressure
> to your crystal, and consequently the band gap increases.
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and this is likely to be the main reason of the discrepancy. Other
factors, such as the pseudopotential, cutoff, number of k-points,
may contribute to the difference. For instance: in GaAs, the use
of a nonrelativistic pseudopotential for Ga increases the band gap
by approx. 0.4 eV.
By the way: the tests and examples are NOT meant to give any
realistic description of any realistic systems.
Paolo Giannozzi e-mail: giannozz at nest.sns.it
Scuola Normale Superiore Phone: +39/050-509876, Fax:-563513
Piazza dei Cavalieri 7 I-56126 Pisa, Italy
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