Tunneling spectroscopy of DC current biased planar Josephson junctions

Time-periodic drive facilitates engineering non-equilibrium quantum systems through hybridization between Floquet sidebands. Floquet driven topological superconductivity may provide additional functionality for quantum devices. Here we detail fabrication and measurement of DC current biased planar Josephson junctions (JJs) in which the intrinsic AC Josephson effect may provide the necessary time-periodic drive needed to support Floquet topological superconductivity. We fabricated planar JJs with two tunneling probes to sense the local density of states at two ends of the junction of a hybrid epitaxial Al-InAs two-dimensional electrons gas (2DEG) heterostructure. We observed four conductance peaks in tunneling spectroscopy when a finite DC voltage bias across the junction is generated by an applied current. We report a systematic study of local conductance as a function of DC voltage bias across junction and as a function applied in-plane magnetic field. We compare our experimental data with theoretical calculations using Floquet theory.