Moiré is Different: Metal-Insulator Transitions, Kondo Lattice Physics and Chiral Spin Liquids in TMD Bilayers

University of Geneva

The greatest open questions in quantum matter physics revolve around strongly correlated electronic phases, traditionally observed in heavy fermions, cuprates and organics. In recent years, a new class of materials emerged where the strength of correlations can be engineered: “moiré materials”. I will briefly introduce moiré materials such as twisted bilayer graphene and transition-metal dichalcogenide (TMD) bilayers. I will then focus on three recent results: a universal theory for continuous metal-insulator transitions [1], valley-charge-transfer and Kondo lattice physics under pressure in TMD homobilayers [2] and our prediction of a chiral spin liquid phase in TMD [3,4]. These results show that the wealth of phenomena observed in moiré materials allow for new insights in old correlated problems.

[1] Simone Fratini, Sergio Ciuchi, Vladimir Dobrosavljevic, Louk Rademaker, Universal scaling near band-tuned metal-insulator phase transitions, Phys. Rev. Lett 131, 196303 (2023); arXiv:2307.09292.
[2] Marta Brzezinska, Sergii Grytsiuk, Malte Rösner, Marco Gibertini, and Louk Rademaker, Tuning interactions using pressure-induced Γ-K valleytronics in moire bilayer WSe2, arXiv: 2404.07165
[3] Dario Rossi, Johannes Motruk, Louk Rademaker, Dmitry A. Abanin, Schwinger boson study of the J1- J2-J3 kagome Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interactions, Phys. Rev. B 108, 144406 (2023); arXiv:2305.15824.
[4] Johannes Motruk, Dario Rossi, Dmitry A. Abanin, Louk Rademaker, Kagome Chiral Spin Liquid in Transition Metal Dichalcogenide Moire Bilayers, Phys. Rev. Research 5, L022049 (2023); arXiv:2211.15696.