Frustrated magnetic interactions in a Wigner-Mott insulator

Abstract

Two-dimensional semiconductor moiré materials have emerged as a highly controllable platform to simulate and explore quantum condensed matter. Compared to real solids, electrons in semiconductor moiré materials are less strongly attracted to the moiré lattice sites, making the nonlocal contributions to the magnetic interactions as important as the Anderson super-exchange. It provides a unique platform to study the effects of competing magnetic interactions. Here, we report the observation of strongly frustrated magnetic interactions in a Wigner-Mott insulating state at 2/3 filling of the moiré lattice in angle-aligned WSe2/WS2 heterobilayers. Magneto-optical measurements show that the net exchange interaction is antiferromagnetic for filling factors below 1 with a strong suppression at 2/3 filling. The suppression is lifted upon screening of the long-range Coulomb interactions and melting of the Wigner-Mott insulator by a nearby metallic gate. The results can be qualitatively captured by a honeycomb-lattice spin model with an antiferromagnetic nearest-neighbor coupling and a ferromagnetic second-neighbor coupling. Our study establishes semiconductor moiré materials as a model system for the lattice-spin physics and frustrated magnetism.

References in corpus (27)

• Observation of Moiré Excitons in WSe2/WS2 Heterostructure Superlattices
• Optical detection of Mott and generalized Wigner crystal states in WSe2/WS2 moiré superlattices
• Magic continuum in twisted bilayer WSe2
• Topological insulators in twisted transition metal dichalcogenide homobilayers
• Hubbard model physics in transition metal dichalcogenide moiré bands
• Charge-ordering, commensurability and metallicity in the phase diagram of layered Na(x)CoO(2)
• Moiré heterostructures as a condensed matter quantum simulator
• Moiré superlattice in a MoSe${}_2$/hBN/MoSe${}_2$ heterostructure: from coherent coupling of inter- and intra-layer excitons to correlated Mott-like states of electrons
• Continuous Mott transition in semiconductor moiré superlattices
• Correlated Insulating States at Fractional Fillings of the WS2/WSe2 Moiré Lattice
• Quantum Criticality in Twisted Transition Metal Dichalcogenides
• Stripe phases in WSe2/WS2 moiré superlattices
• Band topology, Hubbard model, Heisenberg model, and Dzyaloshinskii-Moriya interaction in twisted bilayer WSe${}_2$
• Moiré quantum chemistry: charge transfer in transition metal dichalcogenide superlattices
• Quantum Phase Diagram of a Moiré-Hubbard Model
• Correlated interlayer exciton insulator in double layers of monolayer WSe2 and moiré WS2/WSe2
• Electronic structures, charge transfer and charge orders in twisted transition metal dichalcogenide bilayers
• Temperature Dependence of the Magnetic Susceptibility for Triangular-Lattice Antiferromagnets with spatially anisotropic exchange constants
• Ferromagnetism, paramagnetism and a Curie-Weiss metal in an electron doped Hubbard model on a triangular lattice
• Charge Transfer Excitations, Pair Density Waves, and Superconductivity in Moiré Materials
• Charge-order-enhanced capacitance in semiconductor moiré superlattices
• Non-local interactions in moiré Hubbard systems
• Competing magnetic states in transition metal dichalcogenide moiré materials
• Dielectric catastrophe at the Mott and Wigner transitions in a moiré superlattice
• Triangular lattice Hubbard model physics at intermediate temperatures
• Magnetism and Quantum Melting in Moiré-Material Wigner Crystals
• Light-Induced Ferromagnetism in Moiré Superlattices

Cited by in corpus (34)

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• Interplay between topology and correlations in the second moiré band of twisted bilayer MoTe2
• Progress and Prospects in Two-Dimensional Magnetism of van der Waals Materials
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• Triangular lattice Hubbard model physics at intermediate temperatures
• Magnetism and Quantum Melting in Moiré-Material Wigner Crystals
• Chiral Pseudo Spin Liquids in Moire Heterostructures
• Metal-insulator transition in transition metal dichalcogenide heterobilayer: accurate treatment of interaction
• Kagome chiral spin liquid in transition metal dichalcogenide moiré bilayers
• Probing magnetism in moiré heterostructures with quantum twisting microscopes
• Dimensionality dependent electronic structure of the exfoliated van der Waals antiferromagnet NiPS${}_3$
• Pseudogap metal and magnetization plateau from doping moiré Mott insulator
• Engineering robust strain transmission in van der Waals heterostructure devices
• Mott insulators in moiré transition metal dichalcogenides at fractional fillings: Slave-rotor mean-field theory
• Tunable exciton valley-pseudospin orders in moiré Bose-Hubbard model
• Phonons of electronic crystals in two-dimensional semiconductor moiré patterns
• Pressure-tuned many-body phases through $\Gamma$-K valleytronics in moiré bilayer WSe${}_2$
• Particle-hole asymmetric ferromagnetism and spin textures in the triangular Hubbard-Hofstadter model
• Optical Switching of Moiré Chern Ferromagnet
• Charge and spin properties of a generalized Wigner crystal realized in the moiré WSe${}_2$/WS${}_2$ heterobilayer
• Electronic correlations in epitaxial graphene: Mott states proximitized to a relativistic electron gas
• Kanamori-Moiré-Hubbard model for transition metal dichalcogenide homobilayers
• Itinerant ferromagnetism in transition metal dichalcogenides moiré superlattices
• Magnetic properties of moiré quantum dot arrays
• Observation of Magnon-Polarons in the Fermi-Hubbard Model
• The two-dimensional homogeneous electron gas with symmetric dual-gate screening: exchange-correlation functional and other ground-state properties
• Quantum Spin Liquids in Weak Mott Insulators with a Spin-Orbit Coupling
• Purely electronic model for exciton-polaron formation in moiré heterostructures
• Candidate for a Fractional Topological Insulator in Twisted MoTe2
• Insulating charge transfer ferromagnetism
• Itinerant magnetism in the triangular lattice Hubbard model at half-doping: Application to twisted transition-metal dichalcogenides
• Engineering Hubbard models with gated two-dimensional moiré systems
• Electronic phonon-induced magnetism in moiré Mott-Wigner crystals
• Stripe antiferromagnetism and chiral superconductivity in tWSe${}_2$