Excitonic Bose-polarons in electron-hole bilayers

TL;DR

This paper explores the formation and properties of Bose polarons in electron-hole bilayers, revealing how excitons interact with degenerate Bose gases and demonstrating tunable polaron behaviors through experimental and theoretical analysis.

Contribution

It introduces excitonic Bose polarons in electron-hole bilayers and provides experimental detection and theoretical understanding of their behavior in strongly interacting systems.

Findings

Detection of attractive and repulsive Bose polarons via photoluminescence spectra.

Control of polaron energy splitting through exciton density manipulation.

Agreement between experimental results and theoretical calculations.

Abstract

Bose polarons are mobile impurities dressed by density fluctuations of a surrounding degenerate Bose gas. These many-body objects have been realized in ultracold atomic gasses and become a subject of intensive studies. In this work, we show that excitons in electron-hole bilayers offer new opportunities for exploring polarons in strongly interacting, highly tunable bosonic systems. We found that Bose polarons are formed by spatially direct excitons immersed in degenerate Bose gases of spatially indirect excitons (IXs). We detected both attractive and repulsive Bose polarons by measuring photoluminescence excitation spectra. We controlled the density of IX Bose gas by optical excitation and observed an enhancement of the energy splitting between attractive and repulsive Bose polarons with increasing IX density, in agreement with our theoretical calculations.