Dear All I am plotting density of states for unrelaxed and relaxed calculations of cubic SiC with B, Al and Ga as substitutional impurity. Substitutions are done for both Si and C sites separately. The density plot without relaxation looks OK. But after relaxation the density plot undergoes a drastic change. I am not able to understand whats going wrong. Here I am sending the density plots for all the cases with and without relaxation. In all the figures the top of valence band is taken as zero on the energy axis. Calculations are done with a supercell of 128 atoms with one single impurity atom in it. The dashed (purple)? line is the Fermi energy. The dotted line shows the calculated band gap. I am aslo giving here a portion of the relaxed input file used for calculations.
?&control ??? calculation='relax' ??? restart_mode='from_scratch', ??? prefix='sic', ??? pseudo_dir = '/espresso-4.0.5/pseudo/', ??? outdir='/tmp/' ??? tprnfor= .TRUE. ?/ ?&system ??? ibrav=2, celldm(1) =32.9648, nat=128, ntyp=3, ??? nspin = 2, ??? starting_magnetization(1)=0.0,starting_magnetization(2)=0.0, ??? starting_magnetization(3)=0.0, ??? ecutwfc = 30.0, ??? occupations='smearing', smearing='methfessel-paxton', degauss=0.02 ?/ ?&electrons ??? mixing_beta = 0.7 ?/ &IONS ? pot_extrapolation = "second_order", ? wfc_extrapolation = "second_order", ?/ ATOMIC_SPECIES ?? Si? 28.086?? Si.pz-vbc.UPF ?? C? 12.00???? C.pz-vbc.UPF ?? Al 26.98154? Al.pz-vbc.UPF As ssen in figure after relaxation we found mane levels inside band gap at there is no gap for Al and Ga case. How is this possible? I have also done for few other impurities and in most of the cases the C site substitution after relaxation gives multiple levels inside band gap. Can anybody please clarify whats going wrong? Thanks in advance. regards Padmaja Patnaik Research Scholar Dept of Physics IIT Bombay Mumbai, India -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110609/ccc8b2ba/attachment-0001.htm -------------- next part -------------- A non-text attachment was scrubbed... Name: alldos-2.jpg Type: image/jpeg Size: 149027 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110609/ccc8b2ba/attachment-0002.jpg -------------- next part -------------- A non-text attachment was scrubbed... Name: alldos-re-2.jpg Type: image/jpeg Size: 154627 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110609/ccc8b2ba/attachment-0003.jpg
