[Wien] band structure of Ge in the zinc blende structure

[mokhtari]

Dear Wien users  
I am studing the electronic properties of the Ge  
compound in the zinc blende phase. when I used the LDA  
approximation, I obtained semimetal material. then I  
used different GGA methods but I get a direct band gap  
between Gama-Gama with amount of zero or a smal  
quantity. There are some experimental data for this  
case show that this material has an indirect band gap  
which is Gama-L with value equal to 0.74 eV. Is there  
any body to help me for solving this problem.  
Thank you in advance,  
Yours  
A. Mokhtari