Defect-Driven Superfluid Crossover for Two-Dimensional Dipolar Excitons Trapped at Thermodynamic Equilibrium

Abstract

We study ultra-cold dipolar excitons confined in a 10$\mu$m trap of a double GaAs quantum well. Based on the local density approximation, we unveil for the first time the equation of state of excitons at pure thermodynamic equilibrium. In this regime we show that, below a critical temperature of about $1$ Kelvin, a superfluid forms in the inner region of the trap at a local exciton density $n\sim 2-310^{10}{\text{cm}}^{-2}$, encircled by a more dilute and normal component in the outer rim of the trap. Remarkably, this spatial arrangement correlates directly with the concentration of defects in the exciton density which exhibits a sudden decrease at the onset of superfluidity, thus pointing towards an underlying Berezinskii-Kosterlitz-Thouless mechanism.

8 pages, 8 figures

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Cited by in corpus (10)

• Evidence of high-temperature exciton condensation in 2D atomic double layers
• Spontaneous coherence in spatially extended photonic systems: Non-Equilibrium Bose-Einstein condensation
• Key role of the moire potential for the quasi-condensation of interlayer excitons in van der Waals heterostructures
• Quasi-condensation of bilayer excitons in a periodic potential
• Observation of Algebraic Time Order for Two-Dimensional Dipolar Excitons
• Optical signature of quantum coherence in fully dark exciton condensates
• Exploring the Berezinskii-Kosterlitz-Thouless Transition in a Two-dimensional Dipolar Bose Gas
• A Microscopic Lattice for Two-dimensional Dipolar Excitons
• Signature of electromagnetic quantum fluctuations in exciton physics
• The Role of Spin-Flip Collisions in a Dark Exciton Condensate