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<p>Dear Kefan,</p>
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<p>If you browse the pw_forum archive on this topic, you will find a lot of useful information.</p>
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<p>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). </p>
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<p>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. </p>
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<p>Greetings,</p>
<p>Iurii</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Kefan Chen <kefanc@nevada.unr.edu><br>
<b>Sent:</b> Saturday, February 15, 2020 12:41:02 AM<br>
<b>To:</b> users@lists.quantum-espresso.org<br>
<b>Subject:</b> [QE-users] How to determine hubbard_u and hubbard_alpha on DFT+U</font>
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<div dir="ltr">Hi there,
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<div>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?</div>
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<div>Thank you very much for your help!</div>
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<div>Kefan</div>
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<div>Ph.D. student</div>
<div>Department of Chemical and Materials Engineering</div>
<div>University of Nevada, Reno, USA</div>
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