No subject

structure calculation of several materials using VASP
and SIESTA and obtained the band gaps in excellent agreement with
experiments. So my guess is that they are propagating
the "LDA-1/2" pseudo in the extended system as is.

Hi Layla,

Thanks a lot. I am looking forward to hear from you about the details of
LDA-1/2 in QE-4.3a.

Thanks, and regards,

Rajan

Rajan K. Pandey, Ph.D.

Advisory Research Engineer,
Semiconductor Research & Development Center
India Systems & Technology Engineering Lab
IBM India Pvt. Ltd.
MD3 1F B354
Manyata Embassy  Business Park
Nagawara, Outer Ring Road
Bangalore - 560045, India
Phone: +91-80-28061262
Mobile: +91-9901850981
Email: rajapand at in.ibm.com
            rajanpandey at gmail.com

On Tue, Mar 29, 2011 at 9:17 PM, Layla Martin-Samos
<lmartinsamos at gmail.com>wrote:

> H,
> sometime ago LDA-1/2 in pwscf was working. I saw some numbers for TiO2
> anatase, But I do not remember the details.
>
> i'll ask around
>
> bests regards
>
> Layla
>
>
>
>
> 2011/3/29 Nicola Marzari <nicola.marzari at materials.ox.ac.uk>
>
>>
>>
>> Hi,
>>
>> If I understand correctly, you generated a lda-1/2 pseudo
>> with the atomic code, but did a lda calculation on silicon
>> with pwscf - so you will have gotten very similar but not perfectly
>> identical results, of lda bulk silicon done with a consistent
>> pseudo (lda) or an inconsistent pseudo .
>>
>> 2) not sure if lda-1/2 is in pwscf (I think not) or if it
>> can be applied to solids.
>>
>>                        nicola
>>
>>
>>
>> On 3/29/11 3:28 PM, Rajan Pandey wrote:
>> > Dear Quantum Espresso Community,
>> >
>> > I built the latest release (perhaps alpha) of QE-4.3a. Tried to look
>> > into the latest LDA -1/2 (assumed to be similar to SIC) in atomic code
>> > (ld1), and from the available test case of Silicon,
>> > I decided to check if I get a corrected band gap of bulk Si (from
>> > example05). First I generated LDA - 0.5 pseudo (input deck for the same
>> > is supplied with the distribution). Subsequently,
>> > to run a band structure calculation of Si, I used the template in
>> > example05. First I did band structure calculation with Si.pz-vbc.UPF,
>> > and then another calculation with the LDA - 0.5 pseudo (Si.LDA.0.5.UPF).
>> > I checked the output of scf calculation of the latter (I am copying the
>> > portion from output):
>> >
>> >
>> >       PseudoPot. # 1 for Si read from file Si.LDA.0.5.UPF
>> >       MD5 check sum: ac6493edff0fd6b486246c8fa11d17dc
>> >       Pseudo is Norm-conserving, Zval =  4.0
>> >       Generated using LDA-1/2 implemented by Leonardo Matheus Marion
>> Jorge
>> >       Using radial grid of  431 points,  2 beta functions with:
>> >                  l(1) =   0
>> >                  l(2) =   1
>> >
>> >       atomic species   valence    mass     pseudopotential
>> >          Si             4.00    28.08600     Si( 1.00)
>> >
>> >       48 Sym.Ops. (with inversion)
>> >
>> > However, the end results of the two calculations are the same. That is
>> > the band structure and hence the band gap in two cases are same - nearly
>> > 50% underestimated.
>> > Not sure if I am missing something. I have attached the two scripts:
>> > run_example-0 ==> uses LDA pseudo, and run_example ==> uses LDA - 1/2
>> > pseudo.
>> > I shall appreciate any suggestion.
>> >
>> > Thanks, and regards,
>> >
>> > Rajan
>> >
>> --
>> ----------------------------------------------------------------------
>> Prof Nicola Marzari    Department of Materials    University of Oxford
>> Chair of Materials Modelling  Director, Materials Modelling Laboratory
>> nicola.marzari at materials.ox.ac.uk     http://mml.materials.ox.ac.uk/NM
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
>>
>
>
> _______________________________________________
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>
>

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Hi Nicola,<br><br>Your comment prompted me to get the reference [ L. G. Fer=
reira, M. Marques<br>and L. K. Teles, Phys. Rev. B 78 125116 (2008) ] and t=
ry to figure out the way authors worked out LDA - 1/2 method, in general.<b=
r>