[Wien] A question regarding the calculated values of the DOS - a single unit cell vs a supercell

[Peter Blaha]

The units of the DOS are    states/eV/cell   !!!

Sometimes people quote it as    states/eV/fu (formula unit),
but in a multiatom cell never "per atom".

Am 22.09.2011 09:24, schrieb Qiwen YAO:
> Dear Wien2k users,
> I have a question regarding the calculated values of the DOS - a single unit cell vs a supercell please:
>
> I have a unit cell with 4 atoms in a single cell for the compound of Sr2CoO4, and I was doing the DOS calculation (spin polarized calculation) on it  - and the converged total DOS at EF level was about 2 states/eV spin up and 3 stats/eV spin down (so this is a spin polarized system).
>
> Then I do a 2x2x1 supercell calculation for the same structure (but for a Nd doped compound: Sr1.5Nd0.5CoO4 - one of the Sr out of four was replaced by one Nd - so a supercell is necessary in this case). After the initialization WIEN2k turn the structure into a 13 atom cell for calculation. Here comes the thing confuses me: the calculated total DOS results in the EF level for this supercell seems to be too high - with about 10 states/eV spin up and 30 states/eV spin down.
>
> I was asking someone about this and I was told that I need to divide the resulted DOS values by 4 to get the actual result for a single cell from the supercell calculation - is this correct? But the unit of the DOS is states/eV - would this means it is not atom-number dependent?  If I need to divide it by a number should this number be (13/4) instead of 4 - because WIEN finally calculates the cell as a 13-atom cell, not a 12-atom cell?
>
> I am looking forward to any respond on this - I know this seems to be a simple question for many of you but I am new to Wien2k, sorry for taking up your time on this. But I do want to be clear in this.
>
> Thank you and regards,
>
> Qiwen
>
> **********************************************************
>
> Dr QiWen YAO
> JSPS Fellow
> Multifunctional Materials Group
> Optical and Electronic Materials Unit
> Environment and Energy Materials Research Division
>
> National Institute for Materials Science
>
> 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
> Phone: +81-29-851-3354, ext. no. 6482, Fax: +81-29-859-2501
>
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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