Tunable spin and valley excitations of correlated insulators in $\Gamma$-valley moiré bands

Abstract

Moiré superlattices formed from transition metal dichalcogenides (TMDs) have been shown to support a variety of quantum electronic phases that are highly tunable using applied electromagnetic fields. While the valley character of the low-energy states dramatically affects optoelectronic properties in the constituent TMDs, this degree of freedom has yet to be fully explored in moiré systems. Here, we establish twisted double bilayer WSe${}_2$ as an experimental platform to study electronic correlations within $\Gamma$-valley moiré bands. Through a combination of local and global electronic compressibility measurements, we identify charge-ordered phases at multiple integer and fractional moiré band fillings $\nu$. By measuring the magnetic field dependence of their energy gaps and the chemical potential upon doping, we reveal spin-polarized ground states with novel spin polaron quasiparticle excitations. In addition, an applied displacement field allows us to realize a new mechanism of metal-insulator transition at $\nu =-1$ driven by tuning between $\Gamma$- and $K$-valley moiré bands. Together, our results demonstrate control over both the spin and valley character of the correlated ground and excited states in this system.

References in corpus (16)

• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Moiré heterostructures as a condensed matter quantum simulator
• Quantum anomalous Hall effect from intertwined moiré bands
• Continuous Mott transition in semiconductor moiré superlattices
• Quantum Criticality in Twisted Transition Metal Dichalcogenides
• Tunable bilayer Hubbard model physics in twisted WSe2
• Correlated Hofstadter Spectrum and Flavor Phase Diagram in Magic Angle Graphene
• Charge-order-enhanced capacitance in semiconductor moiré superlattices
• Bilayer WSe${}_2$ as a natural platform for interlayer exciton condensates in the strong coupling limit
• Frustrated magnetic interactions in a Wigner-Mott insulator
• Multifaceted moiré superlattice physics in twisted WSe${}_2$ bilayers
• Competing magnetic states in transition metal dichalcogenide moiré materials
• Itinerant spin polaron and metallic ferromagnetism in semiconductor moiré superlattices
• Dielectric catastrophe at the Mott and Wigner transitions in a moiré superlattice
• Interaction effects and superconductivity signatures in twisted double-bilayer WSe${}_2$
• Light-Induced Ferromagnetism in Moiré Superlattices

Cited by in corpus (23)

• Composite Fermi Liquid at Zero Magnetic Field in Twisted MoTe${}_2$
• Mapping twist-tuned multiband topology in bilayer WSe${}_2$
• Kinetic Magnetism in Triangular Moiré Materials
• Observation of Nagaoka Polarons in a Fermi-Hubbard Quantum Simulator
• Directly imaging spin polarons in a kinetically frustrated Hubbard system
• Itinerant spin polaron and metallic ferromagnetism in semiconductor moiré superlattices
• Hofstadter states and reentrant charge order in a semiconductor moiré lattice
• Metal-insulator transition in transition metal dichalcogenide heterobilayer: accurate treatment of interaction
• Pseudogap metal and magnetization plateau from doping moiré Mott insulator
• Realizing a tunable honeycomb lattice in ABBA-stacked twisted double bilayer WSe${}_2$
• Tuning flat bands by interlayer interaction, spin-orbital coupling, and external fields in twisted homotrilayer MoS${}_2$
• Quantum melting of generalized electron crystal in twisted bilayer MoSe2
• Strong-coupling superconductivity near Gross-Neveu quantum criticality in Dirac systems
• Superconductivity of Incoherent Electrons near the Relativistic Mott Transition in Twisted Dirac Materials
• Long wavelength interdomain phonons and instability of dislocations in small-angle twisted bilayers
• Dirac quantum criticality in twisted double bilayer transition metal dichalcogenides
• Magnetic Hofstadter cascade in a twisted semiconductor homobilayer
• Chern-Selective multi-valley Flat Bands in Twisted Mono-Bilayer and Mono-Trilayer MoTe${}_2$
• Spin-orbital magnetism in moiré Wigner molecules
• Link between thermodynamic correlation signatures and superconductivity in twisted trilayer graphene
• Quasi-bound layer-breathing phonons inside perfect dislocations of lattice-relaxed twisted bilayers
• Itinerant magnetism in Hubbard models with long-range interactions
• Anomalous Landau level gaps near magnetic transitions in monolayer WSe${}_2$