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

[Peter Blaha]

lapwdm needs the occupation numbers in the *weigh* files and without looking into
the code I'm not sure if they are produced by lapw2 with option ROOT.

My advise: use TETRA or TEMP.


Rolando Larico Mamani schrieb:
> Dear Prof. Blaha,
> 
> Thank you very much for your help.
> I still have a doubt about it earlier.
> Professor Blaha, when using LDA+U approximation, the results of the my
> calculations for semiconductors materials are different if I use TETRA or ROOT.
> Which one is correct?
> 
> Calculations with LDA+U approximation, the "ORB" using the density matrix of the
> LAPWDM.
> The subroutines that generate the density matrix are related directly to TETRA
> in the LAPW2?
> If they are related. How the they are related?
> 
> Thank you,
> 
> Rolando.
> 
> _______________________________________________
> Rolando Larico Mamani
> Departamento de Física dos Materiais e Mecânica
> Instituto de Física, Universidade de São Paulo
> Cidade Universitária CEP 05508-090
> Caixa Postal 66318
> São Paulo, SP, Brasil
> e-mail: rlarico at if.usp.br
> 
> 
> Citando Peter Blaha <pblaha at theochem.tuwien.ac.at>:
> 
>> 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,
> 
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                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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