Tunneling between Two Quantum Hall Droplets

TL;DR

This study investigates tunneling between two quantum Hall droplets separated by a high-quality barrier, revealing quantum critical points and scaling behavior similar to quantum Hall transitions, emphasizing the role of interedge correlations.

Contribution

It demonstrates the existence of quantum critical points and scaling laws in tunneling between quantum Hall droplets, highlighting the importance of interedge correlations in these phenomena.

Findings

Identification of quantum critical points between tunneling regimes

Observation of scaling behavior with exponent κ=0.42

Resemblance to quantum Hall-insulator transition

Abstract

We report on tunneling experiment between two quantum Hall droplets separated by a nearly ideal tunnel barrier. The device is produced by cleaved edge overgrowth that laterally juxtaposes two two-dimensional electron systems across a high quality semiconductor barrier. The dramatic evolution of the tunneling characteristics is consistent with the magnetic field-dependent tunneling between the coupled edge states of the quantum Hall droplets. We identify a series of quantum critical points between successive strong and weak tunneling regimes that are reminiscent of the plateau-transitions in quantum Hall effect. Scaling analysis shows that the conductance near the critical magnetic fields $B_{c}$ is a function of a single scaling argument $|B-B_{c}|T^{-\kappa}$, where the exponent $\kappa = 0.42$. This puzzling resemblance to a quantum Hall-insulator transition points to the significance of interedge correlation in the lateral tunneling of quantum Hall droplets.