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Dear users of QE,</div>
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I was running some tests with LiCoO2 within the DFT+U(+V) framework. I decided to compare the DOS obtained by such results and also with the results form materials project (mp-22526). See attached figure.</div>
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<span style="display:inline-block" class="_Entity _EType_OWALink _EId_OWALink _EReadonly_1"><span><span><a href="https://politoit-my.sharepoint.com/:i:/g/personal/lucas_rodriguez_polito_it/EXbhSFxTZgxAk9NHsARA0fIBIpkkw4Wl4OWcb8tJlNNUdw" rel="noopener noreferrer" style="padding: 0px 1px; border-radius: 2px; user-select: all; background-color: rgb(243, 242, 241);" id="OLK_Beautified_a23e60f1-d804-0d6b-47ff-d76c2921ebad" class="OWAAutoLink eScj0 none" data-ogsc=""><img style="width: 16px; height: 16px; vertical-align: middle; padding: 1px 2px 2px 0px;" class="suRDx" alt="" role="presentation" src="https://res.public.onecdn.static.microsoft/assets/mail/file-icon/png/photo_16x16.png">DOS_DFT_MP_UV.png</a></span></span></span></div>
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I expected overestimated U values coming from LR using the hp.x code (U Co-3d ~ 7.7 eV), so that the band gap coming from my results are somewhat high (yellow and red lines in the Fig.).</div>
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What was interesting to me that the results from materials project (which employ DFT+U(+J), with U_eff values coming from LR – see Moore, G. C. et al. Phys. Rev. Mat. 2024) seem to give accurate band gaps (experiments give ~2-2.7 eV). Additionally, it seems
that the Co-3d orbitals are closer to the Ef, which gives a more reasonable picture of the electronic structure.</div>
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How can this be explained considering we are employing the same method? Is it just the inclusion of J values together with the reduction in the U values (considering VASP uses other projectors, PPs...)?</div>
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My initial doubt was coming from the fact that I was unsure how to treat closed-shell systems within the DFT+U framework, before seeing the results in materials project I was planning to test out the U_eff values that I can get from ACBN0, but it is not straightforward...</div>
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Any insights/comments would be appreciated</div>
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Best,</div>
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Lucas F. Rodriguez</div>
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PhD student @ University of Bologna</div>
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