Vortices in dipolar condensates of interlayer excitons

TL;DR

This paper provides a theoretical analysis of vortex properties in dipolar exciton superfluids, revealing unique density redistribution effects and potential transition to a supersolid phase, advancing understanding of excitonic Bose-Einstein condensates.

Contribution

It offers the first detailed theoretical study of vortex behavior in 2D dipolar exciton superfluids, including vortex interactions and lattice formations, considering tunable experimental parameters.

Findings

Density redistribution peaks at vortex edges under strong dipolar interactions

Identification of conditions leading to an exciton supersolid phase

Vortex lattice characteristics depend on dipole moment and exciton density

Abstract

Recently observed signatures of Bose-Einstein condensation and superfluidity of dipolar excitons have drawn enormous attention to excitonic semiconductor bilayers. In superfluids, stabilization and observation of vortex matter is usually a decisive proof of coherent condensation order. However to date, the vortex behavior in a 2D excitonic system with aligned dipole-like interactions that are long-range and everywhere repulsive has not been addressed. We here provide a theoretical description of the vortex characteristics, interaction, and lattices in a dipolar exciton superfluid, solving the corresponding Gross-Pitaevskii equation, while varying the exciton dipole moments and the exciton density - both tunable in the experiment, by interlayer separation and gating, respectively. We draw particular attention to the appearance of a maximum in the density redistribution around the edge of each vortex, in the phase-space region where the dipole interactions are particularly strong, and where a transition to an incompressible exciton supersolid is expected.