Superconducting Quantum Point Contact in epitaxial Al/InAs heterostructures

Superconducting-semiconducting (S-Sm) Josephson junctions facilitate supercurrent flow through discrete Andreev bound states (ABS). In typical planar Josephson junctions there are hundreds of ABS modes and hence spectroscopy of individual ABS modes have been limited to mostly nanowires. In this work, we start with DC measurements of superconducting quantum point contact (QPC). The quality metric of superconducting QPC is quantization of supercurrent where in a microwave spectroscopy set up will exhibit quantized frequency behavior. We discuss various QPC designs and impact of dielectric thickness.