Spin Supercurrent in the Canted Antiferromagnetic Phase

TL;DR

This paper predicts a spin supercurrent in the canted antiferromagnetic phase of bilayer quantum Hall systems, revealing novel spin-charge entanglement phenomena and anomalous Hall resistance behaviors in imbalanced systems.

Contribution

It introduces the concept of a spin supercurrent arising from the canted antiferromagnetic phase, highlighting phenomena unique to imbalanced bilayer quantum Hall systems.

Findings

Supercurrent carrying both spin and charge in each layer.

Anomalous Hall resistance in the zero tunneling limit.

Pure spin supercurrent in counterflow geometry.

Abstract

The spin and layer (pseudospin) degrees of freedom are entangled coherently in the canted antiferromagnetic phase of the bilayer quantum Hall system at the filling factor $\nu =2$. There emerges a complex Goldstone mode describing such a combined degree of freedom. In the zero tunneling-interaction limit ($\Delta_{\text{SAS}}\rightarrow 0$), its phase field provokes a supercurrent carrying both spin and charge within each layer. The Hall resistance is predicted to become anomalous precisely as in the $\nu =1$ bilayer system in the counterflow and drag experiments. Furthermore, it is shown that the total current flowing in the bilayer system is a supercurrent carrying solely spins in the counterflow geometry. It is intriguing that all these phenomena occur only in imbalanced bilayer systems.