<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Padmaja,<div><br></div><div> 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. </div><div><br></div><div>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...</div><div><br></div><div>GS</div><div><br><div><div>Il giorno 04/lug/2010, alle ore 21.56, Padmaja Patnaik ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top" style="font: inherit;">Dear all<br><br>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.<br><br>Padmaja Patnaik<br>
Research Scholar<br>
Dept of Physics<br>
IIT Bombay<br>
Mumbai, India</td></tr></tbody></table><br>
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