Stationary waves in a superfluid exciton gas in quantum Hall bilayers

TL;DR

This paper investigates the formation and characteristics of stationary waves in a superfluid exciton gas within quantum Hall bilayers, emphasizing the effects of imbalance, interlayer distance, and material choices like graphene sandwiches.

Contribution

It demonstrates that stationary waves occur only in imbalanced bilayers within specific current ranges and analyzes how wave patterns change with the d/l ratio and material parameters.

Findings

Stationary waves form only in imbalanced bilayers within certain current ranges.

Wave patterns are qualitatively affected by the d/l ratio.

Graphene-dielectric-graphene sandwiches are suitable for observing these waves.

Abstract

Stationary waves in a superfluid magnetoexciton gas in nu = 1 quantum Hall bilayers are considered. The waves are induced by counter-propagating electrical currents that flow in a system with a point obstacle. It is shown that stationary waves can emerge only in imbalanced bilayers in a certain diapason of currents. It is found that the stationary wave pattern is modified qualitatively under a variation of the ratio of the interlayer distance to the magnetic length d/l. The advantages of use graphene-dielectric-graphene sandwiches for the observation of stationary waves are discussed. We determine the range of parameters (the dielectric constant of the layer that separates two graphene layers and the ratio d/l) for which the state with superfluid magnetoexcitons can be realized in such sandwiches. Typical stationary wave patterns are presented as density plots