[Wien] problem with B.S of InSb and InAs

[Stefaan Cottenier]

> I have calculated the band structure , DOS and optical properties of
> the semiconductors InP, InSb and InAs. The band structure for GaP is
> ok, but for InAs and InSb show overlap around Gamma. that means it
> show them as metallic. i know its wrong result because they are
> semicounductords. So i asking how to solve this problem. Some one
> told me it negative energy gap (the nagative sign means that there is
> overlap around Gamma), is it so? please any one can explain to me
> this... and what the solution..and the discussion for this case..

Band gaps are usually underestimated by LDA/GGA by 50-100%, and often
metallic states are found for materials which are known to be
semiconductors (many, many examples are discussed in the literature).
There is no solution to this within LDA/GGA. For obtaining better
optical properties, you might adjust the band gap to the experimental
one by using the 'sciscors operator' in the input for the optical
programs (see usersguide).

Stfaan