True exciton condensate of one-dimensional electrons through interwire tunneling

Abstract

We theoretically predict that a true bilayer exciton condensate,characterised by off-diagonal long range order and global phase coherence, can be created in one-dimensional solid state electron systems. The mechanism by which this happens is to introduce a single particle hybridization of electron and hole populations, which locks the phase of the relevant mode and hence invalidates the Mermin--Wagner theorem. Electron--hole interactions then amplify this tendency towards off-diagonal long range order, enhancing the condensate properties by more than an order of magnitude over the noninteracting limit. We show that the temperatures below which a substantial condensate fraction would form could reach hundreds of Kelvin, a benefit of the weak screening in one-dimensional systems.