[Pw_forum] how to calculate U parameter

[TRINITE Virginie]

Dear All

I have a related question, coming from elements with semicore states :
Is it possible to have more that one orbital by atoms corrected by the U?
I was thinking that maybe for 3d and 4d elements, it will be meaningful to correct not only the d part but also the semicore states that are very localized.

Best Regards

Dr Virginie Trinite
---------------------------------------
Modeling Infra-Red Lasers and Detectors
III-V Lab THALES Research&  Technology, France

Campus Polytechnique
1, avenue Augustin Fresnel 91767 Palaiseau cedex France

De : pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] De la part de Matteo Cococcioni
Envoyé : vendredi 9 janvier 2015 00:06
À : PWSCF Forum
Objet : Re: [Pw_forum] how to calculate U parameter


Dear Swati,

one possibility is to compute U from linear response as we proposed some year ago in PRB 71 35105 (2005). You can also find a tutorial on this on the webpage:
http://media.quantum-espresso.org/santa_barbara_2009_07/.
As for Se do you really need to use U on it? if so, you have to update the routines set_hubbard_l.f90 and tabd.f90 in order to tell the code what orbital shoudl be corrected by U and how many electrons it should put on them at the beginning of calculation. These routines are contained inside the flib and PW/src/ directories of the code which you then need to recompile.
Best regards,
Matteo

On Thu, Jan 8, 2015 at 6:42 PM, Swati Khatta <swati.khatta at gmail.com<mailto:swati.khatta at gmail.com>> wrote:
Dear all,
I would like to do calculations with  DFT+U of ZnSe material using Quantum esspresso. As per I know there is different U for each distinct type of hubbard atom.And typical value of U is rarely larger than 7-8 eV and in most case it lies between 0<U<5. but how do we know that which value of U satisfied for Zn  atom .Is there we do any type of convergence  to calculate U parameter.
And in case we include U parameter for Se the error has ocurred ' pseduopotential is not inserted yet'. So is it sufficient to not include U parameter for Se to do DFT+U calculations for ZnSe.
Regards
swati khatta
panjab University
chandigarh

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