Mapping the topological proximity-induced gap in multiterminal Josephson junctions

Multiterminal Josephson junctions (MTJJs), devices in which a normal metal is in contact with three or more superconducting leads, have been proposed as artificial analogs of topological crystals.  The topological nature of MTJJs manifests as a modulation of the quasiparticle density of states (DOS) in the normal metal that may be probed by tunneling measurements.  We show that one can reveal this modulation by measuring the resistance of diffusive MTJJs with normal contacts, which shows rich structure as a function of the phase differences $\{\phi_i \}$.  Our approach demonstrates a simple yet powerful technique for exploring topological effects in MTJJs.

Methods
The differential resistance measurements contained within these data sets are taken with lock-in amplifier (LIA) techniques standard to the field. The LIA output along with all other measurement outputs are fed to a digital HP multimeter before being sent to a data acquisition computer via GPIB. Signal binning occurs both within the LIA and within the data acquisition program, and the data sets shown here are the result of both instances of averaging. 

Lead configuration, specific LIA settings, fridge temperature, and any other instrumentation specific to the measurement are described at the header of each .dat file. The units of each measurement channel can be found under Data Input File in the .dat file. 

The plots shown in associated publications are the result of numerically interpellating the data using the Scipy Python package.