Twist to the M-ax(is): A New Moiré Platform Based on M-Point Twisting

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• Dumitru Calugaru, Princeton and Oxford
• Thursday 21 November 2024, 14:00-15:30
• TCM Seminar Room.

If you have a question about this talk, please contact Gaurav.

We introduce a new class of moiré systems based on monolayers with triangular lattices and low-energy states at the M points of the Brillouin zone. These M-point moiré materials differ fundamentally from those derived from Γ- or K-point monolayers, featuring three time-reversal-preserving valleys connected by three-fold rotational symmetry. We propose twisted bilayers of exfoliable 1T-SnSe2 and 1T-ZrS2 as examples of this new class. Using extensive ab initio simulations, we develop continuum models and show that the M-point moiré Hamiltonians exhibit emergent momentum-space non-symmorphic symmetries and a kagome lattice in momentum space. This is the first experimentally viable realization of a projective representation of crystalline space groups in a non-magnetic system. These materials also serve as six-flavor Hubbard simulators with Mott physics, indicated by their flat Wilson loops. Additionally, non-symmorphic momentum-space symmetries make the M-point Hamiltonians quasi-one-dimensional in each valley, suggesting the potential for realizing Luttinger liquid physics. We predict the twist angles for the emergence of flat conduction bands, provide a continuum Hamiltonian, analyze its topology and charge density, and discuss aspects of the physics of this new platform.

This talk is part of the Theory of Condensed Matter series.

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