CMT/LTC Seminars

Kagome chiral spin liquid in transition metal dichalcogenide moiré bilayers

by Johannes Motruk (University of Geneva)




In this talk, I will present results on the state at n=3/4 filling of the flat band in transition metal dichalcogenide moiré bilayers. At this filling, the system can develop charge order in a kagome pattern resulting in localized spins on this lattice geometry. Starting from an extended Hubbard model description, we derive an effective spin model on the kagome lattice and find that its further neighbor spin interactions can be much less suppressed than the corresponding electron hopping strength. Using density matrix renormalization group simulations, we study its phase diagram and, for realistic model parameters relevant for WSe2/WS2, we show that this material can realize the exotic chiral spin liquid (CSL) phase and the highly debated kagome spin liquid. Furthermore, we use the Schwinger boson formalism to investigate the CSL's stability towards anisotropies in the spin couplings. Our work thus demonstrates that the frustration and strong interactions in TMD heterobilayers provide a novel experimental realization of kagome spin models, representing an exciting platform to study spin liquid physics.

Refs.: Phys. Rev. Research 5, L022049 (2023); arXiv:2305.15824

Organized by

Laboratory for Theoretical and Computational Physics

Host: Dr. Markus Müller