[Pw_forum] GGA+U for Germanium, Tin and Silicon

[Giuseppe Mattioli]

Dear Dhirendra

The hubbard_l and hubbard_occ variables identify the angular momentum channel and starting occupation of the electronic shell you are going to correct 
with U, respectively. In the case of Si, Ge and Sn the values are usually set to the same values of C (1 and 2.0), but remember that this correction 
of the p orbitals can, in principle, affect (with weird results) the behavior of s orbitals, which in covalent compounds like molecules (C), and group 
IV semiconductors (C, Si, Ge) are strongly mixed with p orbitals in the so-called hybridized sp, sp2, sp3,... orbitals.
HTH

Giuseppe

On Wednesday, May 20, 2015 11:32:31 PM DHIRENDRA VAIDYA wrote:
> Hi all
> 
> I am trying to use GGA+U in PWSCF. A similar approach as mentioned in
> http://dx.doi.org/10.1063/1.3625939
> 
> Ge, Sn and Si are not listed in flib/set_hubbard_l.f90 and src/tabd.f90.
> Can anyone suggest the 'hubbard_l' value to be set in set_hubbard_l.f90 and
> 'hubbard_occ' in tabd.f90 for Ge, Sn and Si?
> 
> Thanks
> --
> Dhirendra

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   Giuseppe Mattioli                            
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
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