Germanium Band Structure

Total energy, geometry optimization, DFT+U, spin....

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FrancescoMacheda
Posts: 4
Joined: Mon Mar 21, 2016 12:54 pm

Germanium Band Structure

Post by FrancescoMacheda » Mon Mar 21, 2016 1:08 pm

Hi everybody,
I'm new to Abinit. I'm trying to reproduce Germanium band structure with an HGH pseudopotential and spin orbit interaction. It works pretty well, but it fails in reproducing the double degeneracy of the heavy hole at GAMMA point. I post my input:

Code: Select all

# Computation of the band structure.
# First, a SCF density computation, then a non-SCF band structure calculation.

ndtset 2

#Dataset 1 : usual self-consistent calculation
kptopt1 1         

ngkpt1  6 6 6 
nshiftk1 1
shiftk1 0 0 0
prtden1  1   
toldfe1  1.0d-10   

#Dataset 2 : the band structure
iscf2    -2
getden2  -1
kptopt2  -3
nband2  16
ndivk2   40 40 40     
kptbounds2  0.5  0.0  0.0
            0.0  0.0  0.0
            0.0  0.5  0.5
            1.0  1.0  1.0
tolwfr2  1.0d-12
enunit2  1         


#Definition of the unit cell
acell 3*10.67       
rprim  0.0  0.5  0.5   
       0.5  0.0  0.5   
       0.5  0.5  0.0

#Definition of the atom types
ntypat 1         
znucl 32           
               
                         

#Definition of the atoms
natom 2         
typat 1 1         
xred             
           
   0.0  0.0  0.0 
   1/4  1/4  1/4 


ecut 40.0         

#Definition of the SCF procedure
nstep 100         
nspinor=2
optforces 1



Here is what i get:
[img]
http://postimg.org/image/7q8fcqof3/
[/img]
It can be noticed (if not, I assure that zooming it is noticeable) that all the three bands are splitted (wrong). Where is the mistake?

Moreover, if i would like to implement HSE hybrid calculation, it is sufficient to write "ixc=-524" ?

Thank you in advance,
Francesco Macheda
Graduand at Pisa University

Jordan
Posts: 282
Joined: Tue May 07, 2013 9:47 am

Re: Germanium Band Structure

Post by Jordan » Tue Mar 22, 2016 8:33 am

Hi,

No, you cannot use hybrid XC with the current abinit. Maybe soon ...

Jordan

FrancescoMacheda
Posts: 4
Joined: Mon Mar 21, 2016 12:54 pm

Re: Germanium Band Structure

Post by FrancescoMacheda » Tue Mar 22, 2016 9:09 am

Thanks for the reply. As regards the splitting error do you have any suggestion?

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