[Wien] gap

[tran at theochem.tuwien.ac.at]

Hi,

The problem with MBJ is that it can not be used for surfaces or
monolayers the same way as for usual bulk solids. This is because
the average of grad(rho)/rho in the unit cell [in Eq. (3) of PRL 102, 226401 (2009)]
has no meaning when there is vacuum in the unit cell. The only thing you
can do is to fix the value of c [Eq. (3)] by creating case.in0abp (see
user's guide for explanations). You can fix c to the value of the
corresponding bulk solid for instance.

Beside this technical problem, we observed that for monolayer
h-BN and MoS2, MBJ does not really increase the band gap with respect
to PBE.

F. Tran

On Fri, 13 Nov 2015, Brik Hamida wrote:

> Hi
> 
> Im working on  electronic structure  of monolayer material. I  used GGA and MBJ approaches and the obtained gap is very small  in comparaison with
> the experimental result. In the useeguide of wien2k , the authors note that MBJ increase the gap of 3D material and not the 2D one.
> Please can someone advices me which approach (included in wien2k code) allows to increase the gap of the monolayer ??
> Thanks in advance
> Brik      
>