[WIEN]: Bandgaps calculations

[Pablo de la Mora]

Dear WIEN users,
    If the gaps are not correct with the three options in the program; 
then in the case of several bands the bandedges should not be very 
precise. Is that correct?
    For example, in MgB2 there are four bands at Ef, but two of them 
have the upper edge at ~0.8eV is this value correct?
    Is the GGA option 25 stil available and would it give the correct 
values for these cases?
    Yours

          Pablo de la Mora
-------------------------------------------
Peter Blaha wrote:

>====
>Peter Blaha <pblaha at theochem.tuwien.ac.at>
>submitted the following contribution:
>====
>
>  
>
>>I make calculations of AlN,GaN and InN in wurtzite structure using
>>WIEN97.10
>>
>>The bandgaps for AlN y GaN are 50% below of the experimental value, but
>>the bandgap for InN is zero.
>>    
>>
>
>This is what LDA or the common GGAs give.
>
>  
>
>>How I can make calculations more precise of bandgaps in WIEN97.10?
>>    
>>
>
>You can use GGA option 25. This is due to Engel and Vosko. It gives much
>better bandgaps (often even pretty good), but you have to pay a price:
>Never use the total energy! Equillibrium volumes,... are way too large.
>

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