[Pw_forum] MnSe-passivation

[Stefano de Gironcoli]

pristine semiconductor surfaces may show dangling bonds which correspond 
to partially filled electronic surface states in the gap.
Nature dislikes this situation and semiconductor surfaces reconstruct , 
even in rather complicated ways, in order to eliminate these partially 
filled surface states.
Passivating with hydrogen is a computationally easy way to saturate 
these dangling bonds without inducing large reconstructions/relaxations.
If your surface does not show dangling bonds you do not need to 
passivate them.
best,
  stefano

peyman amiri wrote:
> I am working on a (100) free surfaces of NaCl type MnSe structures with (1 1 1) AF order, after passivation of Mn & Se surface atroms by Hydrogen atoms the band gap reduces a little (in compare of free surface without passivation) and from the results of cohesive energy we saw that the free surface MnSe is more stable than the free surface after passivation. Now i am sure that passivation is not needed in my work.
>
> How can i show and prove this matter?
>
> May these results be due to a computational errors? 
>
> In principle when does we need to passive the semiconductor surfaces?  
>
> Any suggestions will be appreciated. 
> Thanks
> Peiman
> ======================================
> Peiman Amiri
> Computational Condensed Matter Research Lab
> Physics Department, Isfahan University of Technology, Iran
>
> Tel lab: +98 311 391 3733 Fax Office: +98311 391 3746 
> ------------------------------ 
>
>
>       
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>