SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 61: Focus Session: Correlations in Moiré Quantum Matter II

TT 61.2: Vortrag

Donnerstag, 30. März 2023, 18:00–18:15, HSZ 201

Switching between Mott-Hubbard and Hund physics in Moiré quantum simulators — •Siheon Ryee and Tim Wehling — I. Institute of Theoretical Physics, University of Hamburg, Hamburg, Germany

Mott-Hubbard and Hund electron correlations have been realized thus far in separate classes of materials. In this talk, we show that a single Moiré homobilayer encompasses both kinds of physics in a controllable manner. We develop a microscopic multiband model which we solve by dynamical mean-field theory to nonperturbatively address the local many-body correlations. We demonstrate how tuning with twist angle, dielectric screening, and hole density allows to switch between Mott-Hubbard and Hund correlated states in twisted WSe₂ bilayer. The underlying mechanism bases on controlling Coulomb-interaction-driven orbital polarization and energetics of concomitant local singlet and triplet spin configurations. From comparison to recent experimental transport data, we find signatures of a filling-controlled transition from a triplet charge-transfer insulator to a Hund-Mott metal. Our finding establishes twisted transition metal dichalcogenides as a tunable platform for exotic phases of quantum matter emerging from large local spin moments.