Autolocalization in a dipolar exciton system

TL;DR

This paper proposes a theory explaining the formation of a macroscopically ordered exciton state in quantum wells through autolocalization driven by dipolar interactions and resonant pairing, suggesting a novel quantum molecular phase.

Contribution

It introduces a new autolocalization hypothesis that accounts for MOES formation considering dipolar interactions and resonant pairing, linking it to a quantum molecular phase.

Findings

Autolocalization can create a periodic localizing potential in exciton systems.

Resonant pairing at short distances influences exciton ordering.

The central incoherent part of MOES may be a quantum molecular phase.

Abstract

We develop the autolocalization hypothesis suggested recently in [Andreev, Phys. Rev. Lett. 110, 146401 (2013)] to explain the formation of the macroscopically ordered exciton state (MOES) in semiconductor quantum wells [L. V. Butov et al., Nature (London) 418, 751 (2002)]. We argue that the onset of a periodical localizing potential having a macroscopic spatial period is possible in the systems where in addition to long-range dipolar repulsion the excitons exhibit resonant pairing at short distances. Our theory suggests, that the central incoherent part of each condensate in the MOES may represent a novel quantum molecular phase, which was predicted and discussed theoretically several years ago in the context of resonant Bose superfluids.