Polariton Bose-Einstein condensate at room temperature in a Al(Ga)N nanowire-dielectric microcavity with a spatial potential trap

TL;DR

This study demonstrates the formation of a room-temperature polariton Bose-Einstein condensate in a specially engineered Al(Ga)N nanowire microcavity with a spatial potential trap, showing potential for solid-state quantum technologies.

Contribution

It introduces a novel spatial potential trap in an Al(Ga)N nanowire microcavity and provides experimental evidence of room-temperature polariton Bose-Einstein condensation.

Findings

Evidence of polariton Bose-Einstein condensate at room temperature.

Evaporative cooling observed during polariton transport.

Condensate formation only occurs with the spatial potential trap.

Abstract

A spatial potential trap is formed in a 6.0 {\mu}m Al(Ga)N nanowire by varying the Al composition along its length during epitaxial growth. The polariton emission characteristics of a dielectric microcavity with the single nanowire embedded in-plane has been studied at room temperature. Excitation is provided at the Al(Ga)N end of the nanowire and polariton emission is observed from the lowest bandgap GaN region of the nanowire. Comparison of the results with those measured in an identical microcavity with an uniform GaN nanowire and having an identical exciton-photon detuning suggests evaporative cooling of the polaritons as they are transported across the trap in the Al(Ga)N nanowire. Measurement of the spectral characteristics of the polariton emission, their momentum distribution, first-order spatial coherence and time-resolved measurements of polariton cooling provide strong evidence of the formation of an equilibrium Bose-Einstein condensate, a unique state of matter in solid state systems, in the GaN region of the nanowire, at room temperature. An equilibrium condensate is not formed in the GaN nanowire dielectric microcavity without the spatial potential trap.