Abstract

Layered bosonic dipolar fluids have been suggested to host a condensate of interlayer molecular bound states. Motivated by recent experimental works, we theoretically study, using numerically exact quantum Monte Carlo calculations, the experimental signatures of collective interlayer pairing in vertically stacked indirect exciton layers. We find that exciton energy shifts associated with each layer evolve nontrivially as a function of density imbalance with a jump discontinuity at density balance, identified with the interlayer exciton molecule gap. This behavior discriminates between the superfluidity of interlayer bound pairs and independent dipole condensation in distinct layers. Considering finite temperature and finite density imbalance conditions, we find a cascade of Berezinskii-Kosterlitz-Thouless transitions, initially into a pair superfluid and only then, at lower temperatures, into complete superfluidity of both layers. The results provide a theoretical interpretation of existing experimental observations in GaAs double quantum well bilayer structures and suggest realistic experimental settings in GaAs and transition metal dichalcogenide bilayer heterostructures where collective interlayer pairing and pair superfluidity can be clearly observed.

Abstract

Layered bosonic dipolar fluids have been suggested to host a condensate of interlayer molecular bound states. Motivated by recent experimental works, we theoretically study, using numerically exact quantum Monte Carlo calculations, the experimental signatures of collective interlayer pairing in vertically stacked indirect exciton layers. We find that exciton energy shifts associated with each layer evolve nontrivially as a function of density imbalance with a jump discontinuity at density balance, identified with the interlayer exciton molecule gap. This behavior discriminates between the superfluidity of interlayer bound pairs and independent dipole condensation in distinct layers. Considering finite temperature and finite density imbalance conditions, we find a cascade of Berezinskii-Kosterlitz-Thouless transitions, initially into a pair superfluid and only then, at lower temperatures, into complete superfluidity of both layers. The results provide a theoretical interpretation of existing experimental observations in GaAs double quantum well bilayer structures and suggest realistic experimental settings in GaAs and transition metal dichalcogenide bilayer heterostructures where collective interlayer pairing and pair superfluidity can be clearly observed.

Abstract

Layered bosonic dipolar fluids have been suggested to host a condensate of interlayer molecular bound states. Motivated by recent experimental works, we theoretically study, using numerically exact quantum Monte Carlo calculations, the experimental signatures of collective interlayer pairing in vertically stacked indirect exciton layers. We find that exciton energy shifts associated with each layer evolve nontrivially as a function of density imbalance with a jump discontinuity at density balance, identified with the interlayer exciton molecule gap. This behavior discriminates between the superfluidity of interlayer bound pairs and independent dipole condensation in distinct layers. Considering finite temperature and finite density imbalance conditions, we find a cascade of Berezinskii-Kosterlitz-Thouless transitions, initially into a pair superfluid and only then, at lower temperatures, into complete superfluidity of both layers. The results provide a theoretical interpretation of existing experimental observations in GaAs double quantum well bilayer structures and suggest realistic experimental settings in GaAs and transition metal dichalcogenide bilayer heterostructures where collective interlayer pairing and pair superfluidity can be clearly observed.

Abstract

Layered bosonic dipolar fluids have been suggested to host a condensate of interlayer molecular bound states. Motivated by recent experimental works, we theoretically study, using numerically exact quantum Monte Carlo calculations, the experimental signatures of collective interlayer pairing in vertically stacked indirect exciton layers. We find that exciton energy shifts associated with each layer evolve nontrivially as a function of density imbalance with a jump discontinuity at density balance, identified with the interlayer exciton molecule gap. This behavior discriminates between the superfluidity of interlayer bound pairs and independent dipole condensation in distinct layers. Considering finite temperature and finite density imbalance conditions, we find a cascade of Berezinskii-Kosterlitz-Thouless transitions, initially into a pair superfluid and only then, at lower temperatures, into complete superfluidity of both layers. The results provide a theoretical interpretation of existing experimental observations in GaAs double quantum well bilayer structures and suggest realistic experimental settings in GaAs and transition metal dichalcogenide bilayer heterostructures where collective interlayer pairing and pair superfluidity can be clearly observed.