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TT: Fachverband Tiefe Temperaturen
TT 7: Correlated Electrons: Electronic Structure Calculations
TT 7.2: Talk
Monday, March 18, 2024, 09:45–10:00, H 3025
Bridging DFT+U and DFT+DMFT: Hartree-Fock approximation and Wannier Projectors — •Alberto Carta1, Iurii Timrov2, Peter Mlkvik1, Alexander Hampel3, and Claude Ederer1 — 1ETH Zurich, Zurich, Switzerland — 2Paul Scherrer Institut, Villigen, Switzerland — 3Flatiron Institute (CCQ), New York, USA
Materials exhibiting strong electron-electron interactions are effectively described by combining density functional theory and dynamical mean-field theory (DFT+DMFT), where electronic correlations are captured by mapping the system to a self-consistently determined impurity model.
By solving the impurity model within the Hartree-Fock approximation, the static-mean field limit of DMFT is recovered. In this contribution we show that DFT+DMFT with the Hartree-Fock approximation is equivalent to the well established DFT+U method.
We demonstrate this equivalence by benchmarking DFT+DMFT calculations against DFT+U for various example systems (MnO, NiO, and LuNiO3), using the new integration of maximally localized Wannier functions as Hubbard projectors in DFT+U as implemented in Quantum ESPRESSO.
Finally, the flexibility of our implementation allows us to extend the application of DFT+U beyond the usual atomic-like orbitals. We explore the use of DFT+U on different basis sets, such as frontier orbitals in LuNiO3 or a molecular orbital-like basis in VO2, showcasing the versatility of our approach.
Keywords: DFT; DMFT; Hartree-Fock; LuNiO3; VO2