[Pw_forum] K-point of silicene

[Ari P Seitsonen]

Dear Andrey,

   You seem to run a super-cell, ie many cells along the 2D plane: Thus 
your band structure gets folded into the small Brillouin zone, and it is 
difficult to find the bands ("Dirac point") as-is. There are references 
now in the literature for un-folding the band structure, I know of one 
tool for doing this (Jonas Björk et co, 
http://www.ifm.liu.se/theomod/compphys/band-unfolding/), or you try 
figuring out the back-folding by first thinking how the Brillouin zones of 
the (1x1) cell and your super-cell would fit and then following the bands 
in your calculation.

     Greetings from Sunny Montrouge,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   Ecole Normale Supérieure (ENS), Département de Chimie, Paris
   Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935


On Fri, 15 Jan 2016, Andrey Chibisov wrote:

> Dear Colleagues.
> I study silicene. My input file is:
>
> &CONTROL
> calculation ='scf',
> restart_mode='from_scratch',
> pseudo_dir = '/Silicene/Espresso',
> outdir = '/Silicene/Espresso/temp',
> /
> &SYSTEM
> ibrav = 4,
> celldm(1) = 29.368422675588050347010890147159,
> celldm(3) = 0.6781823680434460881147409128054,
> nat = 32,
> ntyp = 1,
> ecutwfc = 36,
> occupations = 'smearing',
> smearing = 'gauss',
> degauss = 0.02,
> nosym=.true.,
> nspin = 2, starting_magnetization(1) = 0.4,
> nbnd =135,
> /
> &ELECTRONS
> conv_thr = 1.D-9,
> mixing_beta = 0.3,
> /
> &IONS
> ion_dynamics = 'bfgs',
> /
> &CELL
> cell_dynamics = 'bfgs',
> cell_dofree = 'xy',
> /
> ATOMIC_SPECIES
> Si 28.0855 Si.UPF
> ATOMIC_POSITIONS (crystal)
> Si 0.00137    0.00177    1.00011
> Si 0.08390    0.16877    0.95815
> Si 0.25137    0.00177    1.00011
> Si 0.33390    0.16877    0.95815
> Si 0.50137    0.00177    1.00011
> Si 0.58390    0.16877    0.95815
> Si 0.75137    0.00177    1.00011
> Si 0.83390    0.16877    0.95815
> Si 0.00137    0.25177    1.00011
> Si 0.08390    0.41877    0.95815
> Si 0.25137    0.25177    1.00011
> Si 0.33390    0.41877    0.95815
> Si 0.50137    0.25177    1.00011
> Si 0.58390    0.41877    0.95815
> Si 0.75137    0.25177    1.00011
> Si 0.83390    0.41877    0.95815
> Si 0.00137    0.50177    1.00011
> Si 0.08390    0.66877    0.95815
> Si 0.25137    0.50177    1.00011
> Si 0.33390    0.66877    0.95815
> Si 0.50137    0.50177    1.00011
> Si 0.58390    0.66877    0.95815
> Si 0.75137    0.50177    1.00011
> Si 0.83390    0.66877    0.95815
> Si 0.00137    0.75177    1.00011
> Si 0.08390    0.91877    0.95815
> Si 0.25137    0.75177    1.00011
> Si 0.33390    0.91877    0.95815
> Si 0.50137    0.75177    1.00011
> Si 0.58390    0.91877    0.95815
> Si 0.75137    0.75177    1.00011
> Si 0.83390    0.91877    0.95815
> K_POINTS automatic
> 8 8 1 0 0 0
>
> How I can find the K-point on the band structure?
>
> -- 
> Best regards,
> Andrey Chibisov. Ph.D.
> Numerical method of mathematical physics Laboratory,
> Computational Center, Russian Academy of Sciences.
> Khabarovsk, Russia
> Web page: http://ru.linkedin.com/pub/andrey-chibisov/55/253/986/en
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