On Tue, Nov 18, 2014 at 7:11 PM, SRKC Sharma Yamijala < [email protected]> wrote:
> Dear PW members, > > I have gone through the tutorials of LDA+U available online (mainly of > Matteo Cococcioni and also his PRB 2005 paper). I am interested in > calculating the U for the system SrVO3 and others. If I correctly follow > the tutorial on NiO, to calculate U, I need calculate the scf with 2*2*2 > supercell (and with 4*4*4 etc. till U convergence) by keeping Ni at the > origin once and by keeping O at the origin next. If I follow the above and > consider the 2*2*2 supercell then the number of atoms in my system will be > 40. > > But, I am guessing (I may be wrong) that supercell is considered because > of the AFM nature of NiO ground state. So, can someone please clarify > whether considering supercell is required for non-magnetic/Ferro-magnetic > systems also or not? > > Dear Sharma, NiO needs a unit cell of 4 atoms becaus it is AFM. if it was FM it would be possible to use a cell of 2 atoms only. In both cases you would need to perform the linear response calculation of U in a supercell (of the appropriate cell). Hope this helps Matteo > Thanking you for your support, > Sincerely, > Sharma. > ******************************************************** > *Chaitanya Sharma,* > *Prof. Pati'*s group, > Chemistry and Physics Materials unit, > JNCASR, BANGLORE, > Lab:: (080-2208) 2581, 2809 > https://sites.google.com/site/sharmasrkcyamijala/ > ********************************************************* > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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