Tunneling Spectroscopy of Quantum Hall States in Bilayer Graphene p−n Junctions

摘要

Two dimensional electronic systems under strong magnetic field form quantumHall (QH) edge states, which propagate along the boundary of a sample with adissipationless current. Engineering the pathway of these propagatingone-dimensional chiral modes enables the investigation of quantum tunnelingbetween adjacent QH states. Here, we report tunneling transport in spatiallycontrolled networks of QH edge states in bilayer graphene. We observe resonanttunneling between co-propagating QH edges across barriers formed byelectrically defining incompressible strips. Employing spectroscopic tunnelingmeasurements enable the direct probing of the spatial profile, density ofstates, and compressibility of the QH edge states with an unprecedented energyresolution. The capability to engineer the QH edge network provides anopportunity to build future quantum electronic devices supported by richunderline physics.