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Problem with Band structure Date: 2011/11/08 02:39 Name: Dimpy Sharma Dear Developer. I was trying to obtain band structure calcualtion for hydroxylated Silicon nanowire(Si,H and O) using updated PAO 2011 files,I am getting indirect band structure.While using PAO files from 2006,I got direct band gap.Why does the difference appear?even if using the similar input file in both the cases?Your reply is highly appreciated. Regards Dimpy

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Re: Problem with Band structure ( No.1 ) Date: 2011/11/11 22:06 Name: T.Ozaki Hi, How large difference did you obtain in the two band structures? If the change of the feature (direct to indirect one) is caused by a subtle change of band structure, this kind of thing can happen by changing pseudopotential. For such a case, I think that the assessment should be done using all electron methods in principle. Also I am wondering that you got the convergent result for both the cases with respect to several parameters such as k-points sampling, grid fineness, and basis functions. Regards, TO Re: Problem with Band structure ( No.2 ) Date: 2011/11/14 02:23 Name: Dimpy Sharma Thanks a lot Dr Ozaki, the change in the feature of band from direct to indirect is about 1.757 eV,thus the difference is lot.However the results are converged in both the cases .I used GGA-PBE functional throughout the calculations and the pseudo potential was norm conserving . For s1p1d1 basis sets for Si and O where I get direct band structure,however when I use s2p2d1 or s32p32d1 basis sets for Si and O,I am getting indirect band strcuture with similar coordinates and input. Regards Dimpy Re: Problem with Band structure ( No.3 ) Date: 2011/11/14 17:23 Name: T.Ozaki Hi, I did not mean the SCF convergence by 'convergence', but meant the convergence of electronic band structure with respect to k-points sampling, grid fineness, and basis functions. Did you confirm how the band structure converges as a function of basis function? With the convergent results as for basis function, one can discuss quality of pseudopotential. Regards, TO Re: Problem with Band structure ( No.4 ) Date: 2011/11/15 02:52 Name: Dimpy Sharma Thanks a lot for your reply.I converged the electronic band structure with respect to k-points sampling and grid fitness,howevevr with basis functions ,I only tried with basis sets,s1p1d1,s2p2d1 and s32p32d1 ,but except s1p1d1 basis set ,I get indirect band structure. Regards Dimpy

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