Cascade of Quantum Phase Transitions in Tunnel-Coupled Edge States

TL;DR

This paper investigates a series of quantum phase transitions in tunnel-coupled edge states within a quantum Hall line junction, revealing critical points and scaling behavior indicative of complex interedge correlations.

Contribution

It uncovers a cascade of quantum phase transitions with specific critical points and scaling laws, highlighting the role of interedge correlations in quantum Hall systems.

Findings

Identification of multiple quantum critical points

Scaling behavior with exponent κ=0.42 near critical magnetic fields

Evidence of interedge correlation effects in phase transitions

Abstract

We report on the cascade of quantum phase transitions exhibited by tunnel-coupled edge states across a quantum Hall line junction. We identify a series of quantum critical points between successive strong and weak tunneling regimes in the zero-bias conductance. 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 importance of interedge correlation between the coupled edge states.