Dear Virginie Short answer: It isn't. Realistic answer: Use an EXX functional if you can afford it. Hopeful answer: It will be possible when the DFT+U+V code is released. Very hopeful answer: It would be possible whether the ACBN0 U-based hybrid functional was released.
Dear Swati There is no way to calculate a linear response U for the fully occupied Zn 3d shell. Perform a series of calculations to find semiempirical values of U(Zn) and U(Se) which are suitable for your purposes. For example, try to find U values which reproduce the fundamental band gap of ZnSe *together with* acceptable estimates of its ionization energy and electron affinity. Remember to modify the source code, as pointed out by Matteo, in order to include Se within the "U-able" atoms. HTH Giuseppe On Friday, January 09, 2015 10:17:50 AM TRINITE Virginie wrote: > 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 : [email protected] [mailto:pw_forum- [email protected]] 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 <[email protected]<mailto:[email protected]>> 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 > > _______________________________________________ > Pw_forum mailing list > [email protected]<mailto:[email protected]> > http://pwscf.org/mailman/listinfo/pw_forum > ******************************************************** - Article premier - Les hommes naissent et demeurent libres et ègaux en droits. Les distinctions sociales ne peuvent être fondèes que sur l'utilitè commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la libertè, la propriètè, la sùretè et la rèsistance à l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM) Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <[email protected]> http://www.ism.cnr.it/english/staff/mattiolig ResearcherID: F-6308-2012
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