Thanks very much for your help. I will use the sawtooth potential and see what happens. I will have another look on the band structure as well because I have done the DOS calculations and the graph seems pretty ok..
Regards Elie Date: Wed, 29 Sep 2010 09:55:03 +0200 From: [email protected] To: pw_forum at pwscf.org Subject: Re: [Pw_forum] Bilayer graphene with an electric field applied Dear Elje, since you are dealing with a slab geometry and you want to apply the field along the direction perpendicular to the surface, why don't you use the sawtooth potential (tefield=.TRUE. instead of lefield=.TRUE.) to generate the E field? On 09/28/2010 10:41 PM, Elie Moujaes wrote: Dear all, I I am trying to get the band structure of graphene under the effect of an electric field. The problem is that the result at the end is very messy and jiggly. I repeated the calculations many times but I still get the same result. I first performed a scf calculation without the electric field followed by a scf calculation with an electric field and then the band calculation. Do you have some evidence that your "messy and jiggly" band structure is wrong? Are you sure that you are visualizing it in the correct way? HTH GS SCF with electric field &control prefix='bi elgraphene', calculation='scf', restart_mode='from_scratch', lelfield = .true., 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 = 110.D0,occupations='smearing',smearing='methfessel-paxton', degauss=0.01 / &electrons conv_thr=1.D-10, mixing_mode='plain' efield_cart(1) = 0.0, efield_cart(2) = 0.0, efield_cart(3) = 0.001, startingwfc = 'random' / ATOMIC_SPECIES C 12.0107 C.pz-vbc.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 38 38 1 0 0 0 I noticed that part of the bands calculation output had a problem with the convergence of one of thh eigenavalues as some of the input looked like: per-process dynamical memory: 30.2 Mb Band Structure Calculation Davidson diagonalization with overlap c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged c_bands: 1 eigenvalues not converged Please can anyone suggest me of what could have gone wrong... Thanks Elie Moujaes University of Nottingham NG7 2RD UK _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -- Gabriele Sclauzero, EPFL SB ITP CSEA PH H2 462, Station 3, CH-1015 Lausanne _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100929/a9193dee/attachment-0001.htm
