Cascade of Quantum Phase Transitions in Tunnel-Coupled Edge States

I. Yang, W. Kang, K. W. Baldwin, L. N. Pfeiffer, K. W. West

Published 2003-11-03, updated 2004-02-04Version 2

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.