[Pw_forum] functionals and pseudopotentials for bandgap.

[William Parker]

Hi Eduardo,

TPSS does not significantly change the DFT band gap with respect to PBE.  See these papers:
http://dx.doi.org/10.1063/1.3698285
http://dx.doi.org/10.1063/1.3076922
http://dx.doi.org/10.1063/1.1760074

PBE pseudopotentials have usually been used with HSE since HSE's correlation is the same as PBE.  See, for example:
http://dx.doi.org/10.1063/1.4722993 

The pseudopotentials in PW/examples/EXX_example/pseudos are all RRKJ-type PBE pseudopotentials.  

The first paper I mentioned tested a large number of functionals on a fairly large number of systems.  If you don't like Gaussian basis sets, there is also this paper (no meta-GGAs, though):
http://dx.doi.org/10.1063/1.3524336

Enjoy your exploration of the wide world of density functionals!

--William

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  William D. Parker              phone: +1 (630) 252-3388
  Argonne Scholar
  Argonne Leadership Computing Facility
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  Argonne National Laboratory
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On Sep 26, 2012, at 6:09 AM, Eduardo Ariel Menendez Proupin wrote:

> Dear fellows, 
> 
> I am swimming (but not diving yet) in the sea of hybrid functionals. I need to estimate bandgap corrections of a crystal made of benzene-like molecules. After some googling, I am almost at the same place, but looking to the HSE functional, and I tested the HSE and the TPSS with the example of silicon. I request a few advise, these are my dubts
> 
> 1) Does the metaGGA functional TPSS improves the bandgap ?
> 
> 2) What  pseudopotential (i.e. what functional) can be used for a calculation with HSE?
> 
> 3) What kind of pseudoptential are the CPBE*nlcc.RRKJ3 in   EXX_example
> 
> 4) I would appreciate a recommendation of a published benchmark on the performance of different functionals for the gap. 
> 
> Thanks
> 
> -- 
> 
> 
> Eduardo Menendez Proupin
> Departamento de Química Fisica Aplicada
> Facultad de Ciencias
> Universidad Autónoma de Madrid
> 28049 Madrid, Spain
> Phone: +34 91 497 6706
> 
> On leave from: Departamento de Fisica, Facultad de Ciencias, Universidad de Chile URL: http://fisica.ciencias.uchile.cl/~emenendez
> 
> "Padece, espera y trabaja para gentes que nunca conocerá y que a su vez padecerán, esperarán y trabajarán para otros, que tampoco serán felices, pues el hombre ansía siempre una felicidad situada más allá de la porción que le es otorgada. Pero la grandeza del hombre está precisamente en querer mejorar lo que es. En imponerse Tareas. En el Reino de los Cielos no hay grandeza que conquistar, puesto que allá todo es jerarquía establecida, incógnita despejada, existir sin término, imposibilidad de sacrificio, reposo y deleite. Por ello, agobiado de penas y de Tareas, hermoso dentro de su miseria, capaz de amar en medio de las plagas, el hombre puede hallar su grandeza, su máxima medida en el Reino de este Mundo".
> Alejo Carpentier, El reino de este mundo, (1949).
> 
> "...man never knows for who he suffers and waits. He suffers and waits and works for peoples he will never meet, and who at the same time will suffer and wait and work for others who will also not be happy, as man always desires a happiness that is beyond the lot that he is given. But the greatness of man is precisely in wanting to improve what he is. In assigning himself Tasks. In the Kingdom of Heaven there is no greatness to conquer, for everything there is an established hierarchy, the unknown is unobscured, existence is without end, sacrifice, rest, and delight are impossibilities. Therefore, overwhelmed with hardships and Tasks, beautiful within his misery, capable of loving in the middle of calamity, man can only find his greatness, his full self-realization, in the Kingdom of this World." - Alejo Carpentier
> 
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