The interplay of field-tunable strongly correlated states in a multi-orbital moiré system

Aidan J. Campbell, Valerio Vitale, Mauro Brotons-Gisbert, Hyeonjun Baek, Antoine Borel, Tatyana V. Ivanova, Takashi Taniguchi, Kenji Watanabe, Johannes Lischner, Brian D. Gerardot*

*Corresponding author for this work

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Abstract

The interplay of charge, spin, lattice and orbital degrees of freedom leads to a variety of emergent phenomena in strongly correlated systems. In transition-metal-dichalcogenide-based moiré heterostructures, recent observations of correlated phases can be described by triangular-lattice single-orbital Hubbard models based on moiré bands derived from the Brillouin-zone corners—the so-called K valleys. Richer phase diagrams described by multi-orbital Hubbard models are possible with hexagonal lattices that host moiré bands at the zone centre—called Γ valleys—or an additional layer degree of freedom. Here we report the tunable interaction between strongly correlated hole states hosted by Γ- and K-derived bands in a heterostructure of monolayer MoSe2 and bilayer 2H WSe2. We characterize the behaviour of exciton–polarons to distinguish the layer and valley degrees of freedom. The Γ band gives rise to a charge-transfer insulator described by a two-orbital Hubbard model. An out-of-plane electric field re-orders the Γ- and K-derived bands and drives the redistribution of carriers to the layer-polarized K orbital, generating Wigner crystals and Mott insulating states. Finally, we obtain degeneracy of the Γ and K orbitals at the Fermi level and observe interacting correlated states with phase transitions dependent on the doping density. Our results establish a platform to investigate multi-orbital Hubbard model Hamiltonians.

Original languageEnglish
Pages (from-to)589-596
Number of pages8
JournalNature Physics
Volume20
Issue number4
Early online date30 Jan 2024
DOIs
Publication statusPublished - Apr 2024

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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