Dear Abdul Muhaymen, You say that your results are fine, except the band gap ! How did you correct it in pure ZnS, before Co-doping ? The most commun way in DFT is hybrid functionals (like HSE 06), which obviously are very demanding in computational cost. So the DFT+U (+V) could be a nice alternative. Here I think you might need on-site U not only for Co, but also for Zn (and as you said may be S). Since ZnS is a band insulator and covalent compound, the inter-site V could play an important role. In principle U and V parameters are neither transferable nor universal, but in your case ( calculated U from 8 atoms unit cell to use in 64 atoms supercell), I guess it should be OK !
Best regards ===================================== Dr. Abdesalem HOUARI------------------------------------------------------------------------------------------- Department of physics, Theoretical Physics Laboratory University of Bejaia-06000. Algeria. E-mail: [email protected] & [email protected] https://sites.google.com/site/houariabdeslam/homepage =================================== On Tuesday, 21 May 2024 at 04:17:30 am GMT+1, Abdul Muhaymin via users <[email protected]> wrote: Hello all, I am investigating single TM dopant in wide band gap semiconductors such as Co in ZnS. I am using a 64 atoms supercell where I replaced one of the Zn atom with a Co atom. I tested several convergence with respect to the supercell size. My results seem fine except the band gap. Now I want to apply the U correction to that Co-3d (and maybe to S-2p). For this, is it possible to use the unit cell (8 atoms) and run hp.x to get the U values? Or do I have to run hp.x with the large supercell (2*2*2 unit cell=64 atoms)? Also, at the beginning of our studies, during the structural relaxation phase, we first found our lattice parameter for the host semiconductor from multiple scf calculations and subsequently running an eos analysis (ev.x). Then we ran relax calculation but not vc-relax. We keep this lattice parameter constant and when introducing new dopants, we only vary the atomic positions (calculation='relax'). In this case, when running hp.x, could we replace the vc-relax calculation with relax calculation to self-consistently get the U values? Thanks, Abdul Muhaymin Graduate (MS) student, Materials Science and Nanotechnology Bilkent University, Ankara. _______________________________________________ The Quantum ESPRESSO community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________ The Quantum ESPRESSO community stands by the Ukrainian people and expresses its concerns about the devastating effects that the Russian military offensive has on their country and on the free and peaceful scientific, cultural, and economic cooperation amongst peoples _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
