[Wien] LSDA+Ud+Us

[Gerhard Fecher]

Is anyone able to tell me what is the meaning of applying Hubards U to a free electron
(see unoccupied s bands shown in the paper mentioned below) ?

Ciao
Gerhard

====================================
Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
________________________________________
Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Peter Blaha [pblaha at theochem.tuwien.ac.at]
Gesendet: Montag, 15. Dezember 2008 08:49
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] LSDA+Ud+Us

Try increasing order of the l-values, i.e.
         1  2  0  2            Zn_s and _d

But note: U is applied to the wavefunctions only inside the spheres!
Thus for the delocalized Zn-s function you will never get the
"correct" occupation number, i.e. even a fully occupied orbital (n_s=1)
will have only a very small occupation in APW (maybe even below 0.5 and
thus it may even get shifted in the wrong direction,....

Xu Zuo schrieb:
> Dear Ricardo,
>
> The reason is that applying U only to Zn d orbital is insufficient to
> open the band gap as wide as experimetal result.
>
> Xu
>
> On Mon, Dec 15, 2008 at 11:38 AM, Ricardo Faccio <rfaccio at fq.edu.uy
> <mailto:rfaccio at fq.edu.uy>> wrote:
>
>     Dear Xu
>         Why you selected two L's for applying LDA+U?
>        In my opinion you only need to select your Zn's d orbitals, like
>     this:
>     case.indm or case.indmc
>     =========================================
>     -9.                      Emin cutoff energy
>      1                       number of atoms for which density matrix is
>     calculated
>      1  1  2             Zn_d and _s
>      0  0                 r-index, (l,s)index
>     ==============================
>     The same is valid for your case.inorb file
>     Regards
>     Ricardo
>
>     -------------------------------------------------------------------------
>     -----   Dr. Ricardo Faccio
>
>       Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
>       Facultad de Química, Universidad de la República
>            Av. Gral. Flores 2124, C.C. 1157
>            C.P. 11800, Montevideo, Uruguay.
>       E-mail: rfaccio at fq.edu.uy <mailto:rfaccio at fq.edu.uy>
>       Phone: 598 2 9249859
>                  598 2 9290705
>       Fax:    598 2 9241906
>       Web:  http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
>
>         ----- Original Message -----
>         *From:* Xu Zuo <mailto:xzuonku at gmail.com>
>         *To:* Wien at zeus.theochem.tuwien.ac.at
>         <mailto:Wien at zeus.theochem.tuwien.ac.at>
>         *Sent:* Sunday, December 14, 2008 11:29 PM
>         *Subject:* [Wien] LSDA+Ud+Us
>
>         Dear Colleagues,
>
>         Recently, we found on the literature that it is possible to
>         correct the bandgap of ZnO by applying on-site Coulomb repulsion
>         to both Zn d and s obitals. [1] The LSDA+Ud+Us was originally
>         implimented by FP-LMTO method. We tried to repeat this work
>         using LAPW. Our case.indmc and case.inorb are as followings:
>
>         --------case.indmc--------
>         -9.                      Emin cutoff energy
>          1                       number of atoms for which density
>         matrix is calculated
>          1  2  2  0            Zn_d and _s
>          0  0                   r-index, (l,s)index
>         ------------------------------
>
>         --------case.inorb--------
>           1  1  1                     nmod, natorb, ipr
>         PRATT  1.0                BROYD/PRATT, mixing
>           1  2  2  0                 Zn_d & s
>           1                            nsic 0..AFM, 1..SIC, 2..HFM
>            0.25 0.00               U J (Ry)   Note: we recommend to use
>         U_eff = U-J and J=0
>            3.20 0.00
>         -----------------------------
>
>         We used "runsp_lapw -orb -p -it -ec 0.00001" to run the case.
>         The 1st cycle was OK. In the 2nd cycle, the line "orb -up -p" in
>         the script "runsp" returned with error and was recorded to the
>         case.dayfile. We then tried "x orb -up -p" or "orb uporb.def"
>         from the commandline, which was OK. However, the case.vorbup was
>         empty even after we ran  "x orb -up -p" or "orb uporb.def" from
>         the commandline. To test the program, we also tried only adding
>         Ud. In this case, the program worked fine. We doubt there is
>         something wrong in the input files. Can anybody help us to
>         figure out the correct input files for our case.
>
>         [1] T. R. Paudel et al. Phys. Rev. B 77, 205202 (2008)
>
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>
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                                       P.Blaha
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