Chester supersolid of spatially indirect excitons in double-layer semiconductor heterostructures

TL;DR

This paper predicts and characterizes a supersolid phase of spatially indirect excitons in double-layer semiconductor heterostructures, showing it is experimentally accessible and distinct from other quantum states.

Contribution

It introduces a new supersolid phase of excitons in double-layer structures, with a detailed phase diagram and conditions for experimental realization.

Findings

Supersolid phase exists at small layer separations.

Phase diagram includes supersolid and solid phases.

Supersolid persists up to a solid-solid transition.

Abstract

A supersolid, a counter-intuitive quantum state in which a rigid lattice of particles flows without resistance, has to date not been unambiguously realised. Here we reveal a supersolid ground state of excitons in a double-layer semiconductor heterostructure over a wide range of layer separations outside the focus of recent experiments. This supersolid conforms to the original Chester supersolid with one exciton per supersolid site, as distinct from the alternative version reported in cold-atom systems of a periodic modulation of the superfluid density. We provide the phase diagram augmented by the supersolid. This new phase appears at layer separations much smaller than the predicted exciton normal solid, and it persists up to a solid--solid transition where the quantum phase coherence collapses. The ranges of layer separations and exciton densities in our phase diagram are well within reach of the current experimental capabilities.