[Pw_forum] Bilayer graphene subject to an electric field

Elie Moujaes elie.moujaes at hotmail.co.uk
Mon Dec 13 13:57:36 CET 2010


Dear all,
 
I am trying to get the band structure of bilayer graphene under the effect of an external electric field. I have done the scf calculations without the inclusion of an electric field , then again did teh scf calculation with an electric field included in the z-direction (of value 0.1 Ry). However the convergence is not achieved and it stopped after 100 iterations giving the following message:
 
 
     total cpu time spent up to now is  83435.11 secs

     total energy              =     -52.83248336 Ry
     Harris-Foulkes estimate   =     -45.80937450 Ry
     estimated scf accuracy    <       0.00524127 Ry

     End of self-consistent calculation

     convergence NOT achieved after 100 iterations: stopping

 
You will find below the inout file for the scf calculation when an electric field is applied:
 
 
    &control
    prefix='bielgraphene',
    calculation='scf',
    restart_mode='from_scratch',
    lelfield = .true.,
    nberrycyc= 1,
    pseudo_dir = '/espresso-4.2/pseudo/',
    outdir='/tmp/results_MOUJAES/'
 /
  &system    
    ibrav=  4, celldm(1) =4.608737, celldm(3)=5.330410, nat=4, ntyp= 1,
    ecutwfc = 60.D0,occupations='smearing',smearing='methfessel-paxton', degauss=0.01
/
 &electrons
    conv_thr=1.D-5,     
    mixing_mode='local-TF'
    mixing_beta=0.1D0
    efield_cart(1) = 0.000,
    efield_cart(2) = 0.000,
    efield_cart(3) = 0.10,
    
 /
ATOMIC_SPECIES
 C  12.0107  C.pz-rrkjus.UPF
ATOMIC_POSITIONS crystal
 C 0.000000  0.000000  0.000000  
 C 0.000000  0.000000  0.257692 
 C 0.333333  -0.33333  0.000000  
 C -0.333333  0.33333  0.257692  
 
K_POINTS automatic
   25 25 1  0 0 0  
 
 
Thanks
 
Elie Moujaes
University of Nottingham
NG7 2RD
UK 		 	   		  
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