Dear Padmaja, are you sure that your calculation has been converged wrt the k-point sampling? I believe that if you build the supercell correctly and change the k-point sampling accordingly you'll get the same DOS. In principle this should hold even if you didn't converge wrt the size of the k-point mesh, though not completely sure that this is true also for tetrahedra method occupations.
Please post at least the atomic positions, lattice parameters and the content of the K_POINTS input card, otherwise it will be impossible to help you further... GS Il giorno 04/lug/2010, alle ore 21.56, Padmaja Patnaik ha scritto: > Dear all > > I am studying the properties of a compound semiconductor using super cell > calculations. I have generated super cells by expanding the lattice constant > 2times, 3 times and 4 times in all the directions. My calculations gives > correct results for 2 times and 4 times extended super cells but not for 3 > times extended onel. I have made sure that the generated atomic co-ordinates > are correct. I have tried fixing all the required parameters like, k points, > ecutwfc and nbnd. But still its not working. after doing the scf calculations > I do the DOS with occupations=tetrahedra. But the DOS plot for the second > case is found to be much different from expected while for all other cases > the results match. What can be the probable mistake i am doing? Please > suggest. > > Padmaja Patnaik > Research Scholar > Dept of Physics > IIT Bombay > Mumbai, India > > _______________________________________________ > 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100705/a87dfa32/attachment.htm -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/pkcs7-signature Size: 1753 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20100705/a87dfa32/attachment.bin
