Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 7: Correlated Electrons: Electronic Structure Calculations

TT 7.2: Vortrag

Montag, 18. März 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