Interaction-enhanced flow of a polariton persistent current in a ring

TL;DR

This paper investigates how exciton-polaritons in a ring-shaped structure can be controlled to flow with specific angular momentum states, demonstrating superfluid-like behavior that resists disorder effects.

Contribution

It introduces a resonant-excitation scheme to control polariton flow and winding number, and shows disorder screening as evidence of superfluidity in polariton rings.

Findings

Control of polariton winding number via spin-to-orbital angular momentum conversion

Disorder potential is effectively screened by polariton interactions

Evidence of superfluidity through disorder resilience

Abstract

We study the quantum hydrodynamical features of exciton-polaritons flowing circularly in a ring-shaped geometry. We consider a resonant-excitation scheme in which the spinor polariton fluid is set into motion in both components by spin-to-orbital angular momentum conversion. We show that this scheme allows to control the winding number of the fluid, and to create two circulating states differing by two units of the angular momentum. We then consider the effect of a disorder potential, which is always present in realistic nanostructures. We show that a smooth disorder is efficiently screened by the polariton-polariton interactions, yielding a signature of polariton superfluidity. This effect is reminiscent of supercurrent in a superconducting loop.