High-temperature superfuidity of the two-component Bose gas in a TMDC bilayer

TL;DR

This paper predicts high-temperature superfluidity in a two-component dipolar exciton system within TMDC bilayers, highlighting the enhanced critical temperature due to the two-component nature and potential observable superfluid phenomena.

Contribution

It introduces a theoretical model for superfluidity in two-component dipolar excitons in TMDC bilayers, showing increased critical temperature compared to one-component systems.

Findings

Critical temperature is about ten times higher than in one-component systems.

Sound velocity in two-component exciton gas exceeds that in one-component gas.

Superfluidity could induce observable opposite superconducting currents.

Abstract

The high-temperature superfluidity of two-dimensional dipolar excitons in two parallel TMDC layers is predicted. We study Bose-Einstein condensation in the two-component system of dipolar A and B excitons. The effective mass, energy spectrum of the collective excitations, the sound velocity and critical temperature are obtained for different TMDC materials. It is shown that in the Bogolubov approximation the sound velocity in the two-component dilute exciton Bose gas is always larger than in any one-component. The difference between the sound velocities for two-component and one-component dilute gases is caused by the fact that the sound velocity for two-component system depends on the reduced mass of A and B excitons, which is always smaller than the individual mass of A or B exciton. Due to this fact, the critical temperature Tc for superfluidity for the two-component exciton system in TMDC bilayer is about one order of magnitude higher than Tc in any one-component exciton system. We propose to observe the superfluidity of two-dimensional dipolar excitons in two parallel TMDC layers, which causes two opposite superconducting currents in each TMDC layer.