Fractionalization of Charge Wave Packets at Integer and Fractional Quantum-Hall Y Junctions

Abstract

Low-energy excitation in a quantum Hall system is plasmons at the edge. Coupled plasmon modes in co- and counter-propagating edge channels of integer and fractional quantum Hall systems are experimentally investigated by evaluating fractionalization of charge wave packets. Particularly, the charge mode is well quantized when tunneling between the channels is significant. The scheme can be used to clarify the edge modes in various edge states in topological materials including quantum spin Hall systems.