[Pw_forum] GaAs Band structure
lan haiping
lanhaiping at gmail.com
Fri Aug 28 07:07:00 CEST 2009
Hi,
Several comments:
1, it seems you use NCPP pseudopotentials . Therefore , 40 Ry for enenrgy
cutoff is not enough to get convergent results.
2, You can do alignment of so-called fermi level, which is meaningless
since you deal with a semiconductor.
3, Underestimation of energy gap is well accepted in LDA calculations.
Hope helps
Regards
On Fri, Aug 28, 2009 at 3:37 AM, nand <rana_nand at yahoo.com> wrote:
>
>
> Sir,
> I am a research scholar at the Ranchi university, India. It will be a great
> help if you can help me with the band structure calculation for GaAs using
> Quantum Espresso.
> I do not get the correct band structure even with the input file you
> mentioned below. I am attaching the band structure pdf file which I produced
> using input file given below. As you can see that the fermi level is
> wrongly located and the band gap is badly underestimated. Please tell me
> about the possible fault(s) possible in my calculation.
> Thanking you in advance.
> Nand Rana,
> (Research Scholar)
> Ranchi, India.
>
> -----------------------------------
> input file for the scf calculation:
>
> &control
> calculation='scf',
> outdir='./tmp',
> prefix='gaas',
> pseudo_dir='/espresso-4.0.4/pseudo'
> /
>
> &system
> ibrav=2,
> celldm(1)=10.6827,
> nbnd=8,
> nat=2,
> ntyp=2,
> ecutwfc=40.0d0,
> occupations='fixed',
> nspin=1
> /
>
> &electrons
> conv_thr=1d-6,
> mixing_beta=0.7,
> diagonalization='david'
> /
>
> ATOMIC_SPECIES
> Ga 69.723 Ga.pz-bhs.UPF
> As 74.92160 As.pz-bhs.UPF
>
> ATOMIC_POSITIONS alat
> Ga 0.0 0.0 0.0
> As 0.25 0.25 0.25
>
> K_POINTS automatic
> 10 10 10 0 0 0
>
>
>
>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>
--
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
lanhaiping at gmail.com, hplan at pku.edu.cn
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20090828/d3318080/attachment.html>
More information about the users
mailing list