[Pw_forum] input graphene

[Yamit]

Dear Mr. Oum Chou

The input files for graphene is as follows,

SCF calculation:

&CONTROL
      calculation = 'scf'
      restart_mode='from_scratch'
      prefix='graphene'
      pseudo_dir = $PSEUDO_DIR
      outdir = $TMP_DIR
      /
   &SYSTEM
      ibrav=4
      celldm(1)=4.6595      
      celldm(3)=4.0571     
##(Lattice parameters,a=2.465 A (4.6595 a.u.= experimental value of graphite in-plane lattice constant),and c~10.00A as it is 2D material, do put large vacuum region in z direction to minimize interaction between graphene layers.)
       
      nat=2
      ntyp=1
      ecutwfc=40.0
      ecutrho=200.0
(#modify ecut according to you psp.)
      occupations='smearing'   
 #(Provide small amount of smearing, as graphene is semi-metallic  system.)
      smearing='gaussian'
      nbnd = 8              
      degauss=0.02
      /
   &ELECTRONS
   electron_maxstep = 100
   conv_thr =  1.0e-8
   /
   ATOMIC_SPECIES
   C    12.011    C.#your psp file#.UPF 


  ATOMIC_POSITIONS (angstrom)
   C        0.000000000   0.000000000   0.000000000
   C        1.232850116   0.706423116   0.000000000

#Do fix C atoms, to obtain C-C bond length ~1.42A

   K_POINTS {automatic}
   16 16 1 0 0 0

#(1 k-point is Z-direction, as large vacuum is there.)
(For DOS calculations use a dense grid of k-points e.g. 32x32x1 or better )

Run, nscf calculation (by changing calculation = 'nscf' in scf file).

####################################################################
For DOS calcualtions:

dos.in:
============================
&inputpp
prefix='graphene'
outdir=$TMP_DIR
fildos='graphene.dos'
Emin=-25.0, Emax=20.0, DeltaE=0.1
/
============================
Get Emin & Emax from band structure values.
Just check: "$PATH/espresso-ver/Doc/INPUT_PW.txt" and "$PATH/espresso-ver/Doc/INPUT_DOS.txt" and for details. You can analyse the data in 'graphene.dos',  using gnuplot or xmgrace .

Warm Regards
Amit N. Harode
Applications Group : Computational Materials Simulations
Computational Research Laboratories Ltd.,(CRL INDIA)
Pune - 411004, India.

On Fri, 21 May 2010 17:19:34 +0530  wrote
> I would  like

to ask you some questions about  DOS  of  graphene. I have  some results,  I  have not found a good results .   Could you please  given to me the input file for graphene  (scf) and (dos)



Many thanks



oum.chou
PhD student at UFR-PHE Rabat

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On Fri, 21 May 2010 17:19:34 +0530  wrote
> I would  like

to ask you some questions about  DOS  of  graphene. I have  some results,  I  have not found a good results .   Could you please  given to me the input file for graphene  (scf) and (dos)



Many thanks



oum.chou
PhD student at UFR-PHE Rabat

_______________________________________________

Pw_forum mailing list

Pw_forum at pwscf.org

http://www.democritos.it/mailman/listinfo/pw_forum

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