Leaky exciton condensates in transition metal dichalcogenide moiré bilayers

Abstract

We show that the "dark condensates" that arise when excitons form a Bose-Einstein condensate in a material with an indirect bandgap are not completely dark to optical emission. Rather, such states are "leaky condensates" in which optical emission is facilitated by many-body interactions. We analyze the properties of these leaky condensates in the context of twisted bilayers of transition metal dichalcogenides, which host strongly interacting excitons and an indirect bandgap. We show that this interaction-driven "leaky" emission dominates photoluminescence at low temperatures, with distinctive qualitative features. Finally, we propose that in these materials, unique intervalley physics can lead to crystal symmetry-breaking excitonic ordering, with implications for optical processes.

4+6 pages, 2+1 figures. v2: Forthcoming Letter in Physical Review Research

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Cited by in corpus (11)

• Theory of polar domains in moiré heterostructures
• Extended spatial coherence of interlayer excitons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Exciton-phonon-scattering: A competition between bosonic and fermionic nature of bound electron-hole pairs
• Quantum anomalous Hall effect and electric-field-induced topological phase transition in AB-stacked MoTe${}_2$/WSe${}_2$ moiré heterobilayers
• Collective excitations of a Bose-Einstein condensate of hard-core bosons and their mediated interactions: from two-body bound states to mediated superfluidity
• Non-bosonic moiré excitons
• Moiré exciton condensate: nonlinear Dirac point, broken-symmetry Bloch waves and unusual optical selection rules
• Collective optical properties of moiré excitons
• Searching for Unconventional Superfluid in Excitons of Monolayer Semiconductors
• Fermionic vs. bosonic thermalization in the phonon-driven exciton dynamics: An analytic dimensionality study
• Non-local interactions and supersolidity of moiré excitons