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

[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

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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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