[Pw_forum] problem plotting graphene band structure
Giovanni Cantele
giovanni.cantele at spin.cnr.it
Tue Nov 29 15:15:48 CET 2016
I do not have the time to check the coordinates now, but I guess that the coordinates of the k points are wrong.
If I well remember, for example, the coordinates of the M point are 1/2 (and not 1/3) a reciprocal lattice vector,
so your M point, because you choose crystal coordinates, should look like 0.5 0 0. Maybe other issues are present
for the other k points.
As a minor remark, if you are studying graphene (and not graphite), the coordinate of the A point is not needed
(band structure along a direction where you do not have a true periodicity).
Giovanni
> On 29 Nov 2016, at 13:02, Shan <ecebhushan at gmail.com> wrote:
>
> 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.
>
> <scf.in><bs.in>_______________________________________________
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--
Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74
ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele
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