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

[Qiwen YAO]

Thank you very much professor Blaha and professor Cottenier's responds.

Now that I know the results are all in "states per eV per formula unit", and I don't have to do any manual division to the supercells' results - it make things a bit easier.

Thank you very much.

kind regards,
Qiwen 


------Original Message------
From:"Peter Blaha"<pblaha at theochem.tuwien.ac.at>
To:"A Mailing list for WIEN2k users"<wien at zeus.theochem.tuwien.ac.at>
Cc:
Subject:Re: [Wien] A question regarding the calculated values of the DOS - a single unit cell vs a supercell
Date:09/22/2011 11:05:01 AM(+0200)
>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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>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
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>
>-- 
>
>                                       P.Blaha
>--------------------------------------------------------------------------
>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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**********************************************************

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

**********************************************************