Interedge tunneling in quantum Hall line junctions

We propose a scenario to understand the puzzling features of the recent experiment by Kang and co-workers on tunneling between laterally coupled quantum Hall liquids by modeling the system as a pair of coupled chiral Luttinger liquids with a point contact tunneling center. We show that for filling factors v∼1 the effects of the Coulomb interactions move the system deep into the strong-tunneling regime, by reducing the magnitude of the Luttinger parameter K, leading to the appearance of a zero-bias differential conductance peak of magnitude G_t = Ke²/h at zero temperature. The abrupt appearance of the zero-bias peak as the filling factor is increased past a value v*≳1, and its gradual disappearance thereafter can be understood as a crossover controlled by the main energy scales of this system the bias voltage V, the crossover scale T_K, and the temperature T. The low height of the zero-bias peak ∼0.1e²/h observed in the experiment and its broad finite width can be understood naturally within this picture. Also, the abrupt reappearance of the zero-bias peak for v≳2 can be explained as an effect caused by spin-reversed electrons, i.e., if the 2DEG is assumed to have a small polarization near v ∼2. We also predict that as the temperature is lowered v* should decrease, and the width of the zero-bias peak should become wider. This picture also predicts the existence of a similar zero-bias peak in the spin tunneling conductance near for v≳2.