[Pw_forum] Electric field in silicene

[plgong]

I think the Ecut is small. Did you test the its convergence to total energy? Otherwise, your large electric field maybe lead to the convergence harder.  Try large Ecut and small field, good luck!

在2014-10-21 18:11:15，plgongplgong at theory.issp.ac.cn写道：

Dear all,

I am wanting to get the Dos of silicene under the effect of an external electric field. I have done the scf calculations without electric field , then again did the scf calculation with an electric field included in the z-direction (with value 0.008ua). But the convergence is not achieved and it stopped after 800 iterations and giving it this message:



"total cpu time spent up to now is 20409.6 secs

total energy = -64.27063591 Ry
Harris-Foulkes estimate = -62.93460760 Ry
estimated scf accuracy < 0.00003422 Ry

End of self-consistent calculation

convergence NOT achieved after 800 iterations: stopping"





You will find below  in file for the scf calculation when an electric field is applied:
&control
calculation='scf'
restart_mode='from_scratch',
prefix='elec0.08',
lelfield=.true.,
nberrycyc=3
pseudo_dir ='/home/siham/Desktop/espresso-5.0.1-GPU/pseudo',
outdir='/home/siham/Desktop/espresso-5.0.1-GPU/tmp'
/
&system
ibrav= 1, celldm(1)=10.18, nat= 8, ntyp= 1,
ecutwfc = 20.0
/
&electrons
electron_maxstep=800,
diagonalization='david',
conv_thr = 1.0d-8,
mixing_beta = 0.5,
startingwfc='random',
efield_cart(1)=0.d0,efield_cart(2)=0.d0,efield_cart(3)=0.008d0
/
ATOMIC_SPECIES
Si 28.086 Si.pbe-rrkj.UPF
ATOMIC_POSITIONS
Si -0.125 -0.125 -0.125
Si 0.375 0.375 -0.125
Si 0.375 -0.125 0.375
Si -0.125 0.375 0.375
Si 0.125 0.125 0.125
Si 0.625 0.625 0.125
Si 0.625 0.125 0.625
Si 0.125 0.625 0.625
K_POINTS {automatic}
3 3 7 0 0 0


Thanks in advance


 

 
 


 






 

 



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20141021/9dc24650/attachment.html>