Tunneling at $\nu_T=1$ in Quantum Hall Bilayers

TL;DR

This paper investigates interlayer tunneling in quantum Hall bilayers at total filling factor one, revealing a critical current characteristic of the coherent phase, with temperature-dependent scaling and comparison to Josephson-like behavior.

Contribution

It provides experimental measurements of tunneling properties in quantum Hall bilayers and compares them with theoretical models, highlighting temperature effects and Josephson-like phenomena.

Findings

Critical tunneling current is a robust property of the phase.

Tunneling characteristics match theory at high temperatures.

Zero-bias tunneling resistance decreases significantly at low temperatures.

Abstract

Interlayer tunneling measurements in the strongly correlated bilayer quantized Hall phase at $\nu_T=1$ are reported. The maximum, or critical current for tunneling at $\nu_T=1$, is shown to be a well-defined global property of the coherent phase, insensitive to extrinsic circuit effects and the precise configuration used to measure it, but also exhibiting a surprising scaling behavior with temperature. Comparisons between the experimentally observed tunneling characteristics and a recent theory are favorable at high temperatures, but not at low temperatures where the tunneling closely resembles the dc Josephson effect. The zero-bias tunneling resistance becomes extremely small at low temperatures, vastly less than that observed at zero magnetic field, but nonetheless remains finite. The temperature dependence of this tunneling resistance is similar to that of the ordinary in-plane resistivity of the quantum Hall phase.