Theory of Two-Dimensional Spatially Indirect Equilibrium Exciton Condensates

Abstract

We present a theory of bilayer two-dimensional electron systems that host a spatially indirect exciton condensate when in thermal equilibrium. Equilibrium bilayer exciton condensates (BXCs) are expected to form when two nearby semiconductor layers are electrically isolated, and when the conduction band of one layer is brought close to degeneracy with the valence band of a nearby layer by varying bias or gate voltages. BXCs are characterized by spontaneous inter-layer phase coherence and counterflow superfluidity. The bilayer system we consider is composed of two transition metal dichalcogenide monolayers separated and surrounded by hexagonal boron nitride. We use mean-field-theory and a bosonic weakly interacting exciton model to explore the BXC phase diagram, and time-dependent mean-field theory to address condensate collective mode spectra and quantum fluctuations. We find that a phase transition occurs between states containing one and two condensate components as the layer separation and the exciton density are varied, and derive simple approximate expressions for the exciton-exciton interaction strength which we show can be measured capacitively.

13 pages, 8 figures

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Cited by in corpus (73)

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• Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers
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• Moiré Potential Impedes Interlayer Exciton Diffusion in van der Waals Heterostructures
• Correlated interlayer exciton insulator in double layers of monolayer WSe2 and moiré WS2/WSe2
• Renormalization of quasiparticle band gap in doped two-dimensional materials from many-body calculations
• High-temperature superfuidity of the two-component Bose gas in a TMDC bilayer
• Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers
• Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures
• Exciton condensate in bilayer transition metal dichalcogenides: strong coupling regime
• Towards superfluidity of dipolar excitons in a TMDC double layer
• Superfluidity of Dipolar Excitons in a Black Phosphorene Double Layer
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• Heterobilayers of 2D materials as a platform for excitonic superfluidity
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• Electrically Controlled Two-Dimensional Electron-Hole Fluids
• Gate tuning from exciton superfluid to quantum anomalous Hall in van der Waals heterobilayer
• Electrical Reservoirs for Bilayer Excitons
• Time-Reversal Symmetry-Breaking Nematic Insulators near Quantum Spin Hall Phase Transitions
• On the Optical Properties of Excitons in Buckled 2D Materials in an External Electric Field
• Charge transfer dynamics in MoSe${}_2$/hBN/WSe${}_2$ heterostructures
• Polaron spectroscopy of a bilayer excitonic insulator
• Theory of competing excitonic orders in insulating WTe${}_2$ monolayers
• Geometric Stiffness in Interlayer Exciton Condensates
• Leaky exciton condensates in transition metal dichalcogenide moiré bilayers
• Quantum anomalous Hall effect and electric-field-induced topological phase transition in AB-stacked MoTe${}_2$/WSe${}_2$ moiré heterobilayers
• Electrically tunable dipolar interactions between layer-hybridized excitons
• Keldysh field theory of dynamical exciton condensation transitions in nonequilibrium electron-hole bilayers
• Dynamical exciton condensates in biased electron-hole bilayers
• Microscopic Theory of Equilibrium Polariton Condensates
• Instability and topological robustness of Weyl semimetals against Coulomb interaction
• Controlled Interlayer Exciton Ionization in an Electrostatic Trap in Atomically Thin Heterostructures
• Effects of Disorder on the Transport of Collective Modes in an Excitonic Condensate
• In-plane magnetic field induced density wave states near quantum spin Hall phase transitions
• Modulated phases of graphene quantum Hall polariton fluids
• Electrical Breakdown of Excitonic Insulator
• Optical Signatures of Moiré Trapped Biexcitons
• Anisotropic superfluidity of two-dimensional excitons in a periodic potential
• Ultrafast creation and melting of nonequilibrium excitonic condensates in bulk WSe${}_2$
• Strong-coupling theory of condensate-mediated superconductivity in 2D materials
• Quantum transport simulation of exciton condensate transport physics in a double layer graphene system
• Excitons in planar quantum wells based on transition metal dichalcogenides
• Electrical Control of Two-Dimensional Electron-Hole Fluids in the Quantum Hall Regime
• Analytical Quantitative Semi-Classical Approach to the LoSurdo-Stark Effect and Ionization in 2D excitons
• Superfluidity of dipolar magnetoexcitons in doped double-layered $\alpha$-${\mathcal{T}}_3$ lattice in a strong magnetic field
• Excitonic phases in a spatially separated electron-hole ladder model
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• Searching for Unconventional Superfluid in Excitons of Monolayer Semiconductors
• Superfluidity of a rarefied gas of electron-hole pairs in a bilayer system
• Superfluidity of dipolar excitons in a double layer of $\alpha -T_3$ with a mass term
• Coulomb effects on topological band inversion in the moiré of WSe${}_2$/BAs heterobilayer
• On superfluidity of indirect excitons in transition metals trichalcogenides van der Waals heterostructures
• Quantum Oscillation in Excitonic Insulating Electron-Hole Bilayer
• Electron-hole superfluidity controlled by a periodic potential
• Stationary waves in a superfluid gas of electron-hole pairs in bilayers
• Transition to a supersolid phase in a two-dimensional dilute gas of electron-hole pairs
• Exciton-exciton Interactions -- A Quantitative Comparison Between Complimentary Phenomenological Models
• Energetic comparison of exciton gas versus electron-hole plasma in a bilayer two-dimensional electron-hole system
• Strong enhancement of third harmonic generation in a double layer graphene system caused by electron-hole pairing
• High-temperature tunable superfluidity of polaritons in Xene monolayers in an optical microcavity
• Exciton Superfluidity in 2D Heterostructures from First Principles: The importance of material specific screening
• Anderson-Bogoliubov and Carlson-Goldman modes in counterflow superconductors: Case study of a double monolayer graphene
• Effect of exciton-phonon coupling on the interlayer excitons in transition metal dichalcogenides double layers
• Identifying topological excitonic insulators via bulk-edge correspondence
• Non-Fermi Liquids from Subsystem Symmetry Breaking in van der Waals Multilayers
• Longitudinal Josephson effect in systems with pairing of spatially separated electrons and holes
• 2D bilayer electron-hole superfluidity with unequal and anisotropic masses
• Unconventional superconductivity mediated by exciton density wave fluctuations
• Ab initio Approach to Collective Excitations in Excitonic Insulators
• Fractional spin Josephson effect in topological spin superconductors
• Interaction effects on electronic Floquet spectra: Excitonic effects