Dear Kefan,
If you browse the pw_forum archive on this topic, you will find a lot of useful information. Hubbard_alpha is used in the framework of constrained DFT (linear response approach), using supercells. Please see M. Cococcioni and S. de Gironcoli, Phys. Rev. B 71, 035105 (2005). But there is a more user-friendly way to compute Hubbard U from first principles. It is based on density functional perturbation theory (DFPT). The value of computed U is exactly the same as if you obtain it using the constrained DFT approach mentioned above. Please have a look at this paper: I. Timrov, N. Marzari, and M. Cococcioni, Phys. Rev. B 98, 085127 (2018). Please use the latest version of Quantum ESPRESSO 6.5 : there is a code called HP for calculation of U using DFPT. Greetings, Iurii -- Dr. Iurii Timrov Postdoctoral Researcher STI - IMX - THEOS and NCCR - MARVEL Swiss Federal Institute of Technology Lausanne (EPFL) CH-1015 Lausanne, Switzerland +41 21 69 34 881 http://people.epfl.ch/265334 ________________________________ From: users <[email protected]> on behalf of Kefan Chen <[email protected]> Sent: Saturday, February 15, 2020 12:41:02 AM To: [email protected] Subject: [QE-users] How to determine hubbard_u and hubbard_alpha on DFT+U Hi there, I'm running a calculation with MnO, which I think requires DFT+U feature of QE. However, I don't know how to find an appropriate value for hubbard_u and hubbard_alpha. Could you please guide me on finding the correct value for my calculation? Thank you very much for your help! Kefan Ph.D. student Department of Chemical and Materials Engineering University of Nevada, Reno, USA
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