Bilayer WSe${}_2$ as a natural platform for interlayer exciton condensates in the strong coupling limit

Abstract

Exciton condensates (EC) are macroscopic coherent states arising from condensation of electron-hole pairs. Bilayer heterostructures, consisting of two-dimensional electron and hole layers separated by a tunnel barrier, provide a versatile platform to realize and study EC. The tunnel barrier suppresses recombination yielding long-lived excitons. However, this separation also reduces interlayer Coulomb interactions, limiting the exciton binding strength. Here, we report the observation of EC in naturally occurring 2H-stacked bilayer WSe${}_2$. In this system, the intrinsic spin-valley structure suppresses interlayer tunneling even when the separation is reduced to the atomic limit, providing access to a previously unattainable regime of strong interlayer coupling. Using capacitance spectroscopy, we investigate magneto-EC, formed when partially filled Landau levels (LL) couple between the layers. We find that the strong-coupling EC show dramatically different behaviour compared with previous reports, including an unanticipated variation of the EC robustness with the orbital number, and find evidence for a transition between two types of low-energy charged excitations. Our results provide a demonstration of tuning EC properties by varying the constituent single-particle wavefunctions.

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Cited by in corpus (29)

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• Every-other-layer Dipolar Excitons in a Spin-Valley locked Superlattice
• Robust Interlayer-Coherent Quantum Hall States in Twisted Bilayer Graphene
• Leaky exciton condensates in transition metal dichalcogenide moiré bilayers
• Geometric Stiffness in Interlayer Exciton Condensates
• Electrically tunable dipolar interactions between layer-hybridized excitons
• Dynamical exciton condensates in biased electron-hole bilayers
• Evidence for a Superfluid-to-solid Transition of Bilayer Excitons
• Robust magnetic proximity induced anomalous Hall effect in a room temperature van der Waals ferromagnetic semiconductor based 2D heterostructure
• Optical signatures of interlayer electron coherence in a bilayer semiconductor
• Orbitally controlled quantum Hall states in decoupled two-bilayer graphene sheets
• Uncovering the spin ordering in magic-angle graphene via edge state equilibration
• Interlayer excitonic insulator in two-dimensional double-layer semiconductor junctions: An explicitly solvable model
• Controllable spin splitting in 2D Ferroelectric few-layer ${$γ}$-GeSe
• Hetero-Orbital Two-Component Fractional Quantum Hall States in Bilayer Graphene
• Interface engineering of van der Waals heterostructures towards energy-efficient quantum devices operating at high temperatures
• Designing exciton-condensate Josephson junction in quantum Hall heterostructures
• Electrical Control of Excitons in Bare-MoSe2 and MoSe2/NbSe2 Heterostructure
• Non-Fermi Liquids from Subsystem Symmetry Breaking in van der Waals Multilayers
• Nested Fermi surfaces and correlated electronic phases in hole-doped semiconductor quantum wells
• Stabilization of sliding ferroelectricity through exciton condensation
• Anomalous Landau level gaps near magnetic transitions in monolayer WSe${}_2$
• Emergence of a condensate with finite-energy Cooper pairing in hybrid exciton/superconductor systems
• Residual quantum coherent electron transport in doped graphene leads
• Unconventional superconductivity mediated by exciton density wave fluctuations
• Brightening interlayer excitons by electric-field-driven hole transfer in bilayer WSe2
• Interlayer exciton condensates between second Landau level orbitals in double bilayer graphene
• Correlated interlayer quantum Hall state in large-angle twisted trilayer graphene