Dear Anish Il giorno mar 23 nov 2021 alle ore 07:10 Anish Das <[email protected]> ha scritto:
> Dear experts, > > I am interested in calculating Hubbard-U in self consistent and and site > dependent manner as i am dealing with local point defect and expecting > different charged states near the defect. First, I activated the U > calculation machinaries by applying very small U value (10^-8).Then I > perturbed the inequivalent open-shell Hubbard sites and got 1st shot of U > values (for different sites). Then I am supposed to use new values of U and > again go for the 2nd shot U calculation. > > Now my questions are. > > 1) Should i relax the structure with U values calculated from 1st shot > then go for the 2nd shot? Or i just simply plugin the new U, do SCF and go > for the 2nd shot U-calculation. Dr. Iurii Timrov mentioned to relax the > structure everytime with new U values in his paper. But my structure is > large and has 52 Hubbard sites (159 total atoms). > > there is no rule. depends on your system and on what you want to do. In principles there is always some depenence of U on the structure (and viceversa). How large this dependence is nobody knows before testing. > 2) As i mentioned earlier that my system has 52 inequivalent Hubbard > sites, so 1st i perturbed the all sites and get the 1st shot of U. Then i > relaxed the structure with new U's. Now after the relaxation when i check > the inequivalent Hubbard sites for 2nd shot U calculation (by hp.x), it is > now showing i have 48 Hubbard sites (instead of 52) to be perturbed. My > question is, should i need to perturb the 52 sites (determined during the > 1st shot) or 48 sites (determined during 2nd shot calculation)? > probably your crystal has become more symmetric and Hubbard atoms got a more similar environment to one another. that can happen. Probably your starting structure was a bit disordered and its now going to the near symmetric minimum of energy. Just guessing. Please add your affiliation. Hope this helps. Matteo > > Thanking you > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users -- Matteo Cococcioni Department of Physics University of Pavia Via Bassi 6, I-27100 Pavia, Italy tel +39-0382-987485 e-mail [email protected] <[email protected]>
_______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
