[Wien] LDA+U and Supercell: TETRA or ROOT in case.in2c?

Peter Blaha pblaha at theochem.tuwien.ac.at
Wed Dec 2 07:49:20 CET 2009


I have not used ROOT for several years!

Use TETRA or TEMP. The choice between them is sometimes a matter of taste.

Personally I prefer TETRA (since in principle it gives the correct 
occupation at T=0.
However, it may require more k-points, ....

TEMP definitely helps scf-convergence (the larger the broadening,
e.g. > 0.020, the more it helps), but it may be dangerous since too 
large broadening leads to a "wrong" occupation and in magnetic systems 
the magnetic moment can be too small (or even vanish). Thus try to keep 
the broadening as small as possible (well below 0.010 ) and test it for 
your case and k-mesh.

Rolando Larico Mamani schrieb:
> Dear Prof. Blaha and Wien-users,
> 
> I use a supercell of 72 atoms to my calculations of semiconductors (GaN), in
> this case I use a few k's points (1 and 2) and in my case.in2c I use ROOT.
> 
> So, to an LDA+U calculation (U in Ga) is necessary to change for TETRA in
> case.in2c?
> 
> Best regards,
> 


More information about the Wien mailing list