Quantum interference on a topological insulator surface

Recently, high-quality thin films of cadmium arsenide (Cd₃As₂) have emerged as a promising platform for the observation of quantum transport phenomena and the realization of new topological states.  Electronic quantum interference is a key ingredient in several approaches for topological quantum information processing.  Here, we report on two distinct quantum interference phenomena, namely an Aharonov–Bohm (AB)-like effect and Fabry-Perot reflections, in nanoscale p-n junctions fabricated on thin films of Cd₃As₂, which are in a topological insulator-like state.  Conductance oscillations at small magnetic fields are AB-like.  We discuss their origins and connection to the junction regions.  Concurrently, conductance oscillations that are periodic with gate voltage can also be observed.  We discuss these oscillations in terms of the collimating effect of the junctions.