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TT: Fachverband Tiefe Temperaturen
TT 7: Correlated Electrons: Electronic Structure Calculations
TT 7.8: Talk
Monday, March 18, 2024, 11:30–11:45, H 3025
Dynamical mean-field theory study of the spin-orbit insulator Ba2IrO4: the role of spin-orbit coupling in the Mott transition — •Francesco Cassol1, Léo Gaspard2, Michele Casula1, Cyril Martins2, and Benjamin Lenz1 — 1IMPMC, Sorbonne University - CNRS, Paris, France — 2LCPQ, Université Paul Sabatier Toulouse III - CNRS, Toulouse, France
The discovery of the spin-orbit (SO) induced insulating ground state in Sr2IrO4 has triggered intense resarch efforts targeting materials with strong SO coupling. We focus here on Ba2IrO4, a sister compound of Sr2IrO4 with similar properties. In Ba2IrO4, the absence of structural distortions yields pseudo-spin states that are close in energy, casting doubts on the single band jeff=1/2 picture invoked for Sr2IrO4. Its simple structure makes Ba2IrO4 also an ideal candidate to systematically study the interplay between SO coupling and Coulomb interactions in the metal-insulator transition. Based on an effective three-band model of Ba2IrO4, we investigate the evolution of the Mott transition within dynamical mean-field theory (DMFT). The corresponding phase diagram is studied with respect to the variation of the relevant couplings and temperature. We clarify the topological role of SO coupling and show that the paramagnetic insulating phase is recovered for realistic electron-electron interactions, thus establishing Ba2IrO4 as a SO-induced Mott insulator. Comparing our calculations with available angle-resolved photoemission spectra, we finally discuss the limitations of a single-site DMFT treatment and the role of antiferromagnetic fluctuations.
Keywords: iridates; dynamical mean-field theory; strong spin-orbit coupling; Mott insulator; spectral function