[Pw_forum] problem plotting graphene band structure

[Andrey Chibisov]

Dear B.S. Bhushan,
I see you're from Gwalior. I know this institution. 
Unless, of course I was not mistaken. Give please greetings to Dr. Anurag Srivastava.
And now, with regard to the graphene.
1. The structure must be relaxing.
2. Add the nbnd parameter (with empty state), to watch the band gap.
3. In the graphene there is a spin-orbit interaction. Use the options:
noncolin, lspinorb, starting_magnetization and Fully-Relativistic Pseudo to get a good value bandgap.

So, I hope it will help.

29.11.2016, 22:03, "Shan" <ecebhushan at gmail.com>:
> Dear Experts,
>
> I am beginner of QE. As part of the practice, I am extracting the basic structural and electronic properties of simple semiconducting materials, 1D and 2D structures. Things were fine untill i tried graphene. However, I stuck with graphene band structure for the last 3 days. As a beginner, I have done everything i can to resolve the problem. when i try to plot the band structure of 2 atom graphene, either i get a wrong band gap or an empty plot.
>
> Here I am attaching the SCF code and Bandstructure code. Can someone please verify and tell me where the problem is.
>
> SCF code:-
>
> &CONTROL
>   calculation='scf',
>   outdir='.',
>   prefix='pwscf',
>   pseudo_dir='.',
>   verbosity='low',
>   tprnfor=.true.,
>   tstress=.true.,
> /
>
> &SYSTEM
>   ibrav=4,
>   celldm(1)=4.6509939378d0, celldm(3)=4.536666,
>   nat=2,
>   ntyp=1,
>   ecutwfc=30,
>   ecutrho=120,
>   input_dft='pbe',
>   occupations='smearing',
>   smearing='mv',
>   degauss=0.005d0,
> /
>
> &ELECTRONS
>   conv_thr=1d-08,
>   mixing_beta=0.7d0,
> /
>
> ATOMIC_SPECIES
>   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
>
> ATOMIC_POSITIONS {crystal}
>    C   0.0000000000d0   0.0000000000d0   0.0000000000d0
>    C   0.3333333333d0   0.6666666667d0   0.0000000000d0
>
> K_POINTS {automatic}
>   22 22 1 0 0 0
>
> Band Structure code:-
>
> &CONTROL
>   calculation='bands',
>   outdir='.',
>   prefix='pwscf',
>   pseudo_dir='.',
>   verbosity='high',
> /
>
> &SYSTEM
>   ibrav=4,
>   celldm(1)=4.6509939378d0, celldm(3)=4.536666,
>   nat=2,
>   ntyp=1,
>   ecutwfc=30,
>   ecutrho=120,
>   input_dft='pbe',
>   occupations='smearing',
>   smearing='mv',
>   degauss=0.005d0,
> /
>
> &ELECTRONS
>   conv_thr=1d-08,
>   mixing_beta=0.7d0,
> /
>
> ATOMIC_SPECIES
>   C 12.010700d0 C.pbe-n-rrkjus_psl.0.1.UPF
>
> ATOMIC_POSITIONS {crystal}
>    C   0.0000000000d0   0.0000000000d0   0.0000000000d0
>    C   0.3333333333d0   0.6666666667d0   0.0000000000d0
>
> K_POINTS {crystal_b}
> 5
>   0.000 0.0 0.16666667 10 ! A
>   0.000 0.000 0.0 20 ! G
>   0.33333333 0.57735027 0.0 20 ! K
>   0.33333333 0.0 0.0 20 ! M
>   0.0 0.0 0.0 0 ! G
>
> Thank you very much in advance,
>
> Regards,
> B S Bhushan
> Ph.D Scholar
> Indian Institute of Information Technology and Management, Gwalior,
> India.
>
> ,
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum


-- 
Best regards,
Andrey Chibisov. Ph.D.
Numerical method of mathematical physics Laboratory,
Computational Center, Russian Academy of Sciences.
Khabarovsk, Russia
Web page: https://www.researchgate.net/profile/A_Chibisov
http://ru.linkedin.com/pub/andrey-chibisov/55/253/986/en