DOI: 10.5061/dryad.kh18932hk
title: Data from: Mapping the topological proximity-induced gap in multiterminal Josephson junctions

description: 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.
description: 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 <em><strong>Data Input File</strong></em> in
 the .dat file.  The plots shown in associated
 publications are the result of numerically interpellating the data using
 the Scipy Python package.
description: # Data from: Mapping the topological proximity-induced gap in
 multiterminal Josephson junctions
 [https://doi.org/10.5061/dryad.kh18932hk](https://doi.org/10.5061/dryad.kh18932hk) ## Description of the data and file structure The 2D phase space is mapped using four-terminal resistance measurements. Since the phase difference between each Josephson junction is controlled by flux-biasing a loop, the x- and y-axis of the phase space is the current through each field coil independently coupled to separate flux loops. Contained within each .dat file are specific lead configurations, measurement units, fridge temperature, lock-in amplifier settings, and details on any other instrumentation used for that particular data set. The file structure is generally organized top down as follows: measurement notes in ***Notebook***, a ***RunFile*** containing the routine to increment data traces through the chosen parameter space, a ***DataInputFile*** listing the measurement channels and corresponding units, a ***PlottingFile*** which live plots the trace (not shown) and a ***Tableau*** containing the raw data separated into as many columns as there are measurement channels. ### Files and variables Channels measured in each file include combinations of the following variables: mixing chamber (or sample) temperature in Kelvin, time in seconds, perpendicular magnetic field in gauss, field coil current bias in microamps, and 4-terminal resistance in ohms. #### File: dATPZeta\_No1-6.dat **Description:** Four-terminal magnetoresistance on mesoscopic Au meander line to quantify the effect of weak localization and thus the electron phase coherence lengths of the Au used in the device. #### File: dATPZeta\_No1-16.dat **Description:** Hysteretic magnetoresistance of central device at base temperature showing effects of screening current. #### File: dATPZeta\_No1-20.dat **Description:** Flux popping from reversal of screening current appears as abrupt changes in resistance measured as a function of current through one field coil (flux through one flux loop). #### File: dATP2.0\_300mK.dat **Description:** Four-terminal resistance of the device as a function of current through each field coil perform at 300 mK on sample 2. #### File: modified\_dATPZeta\_No1-42.dat **Description:** Four-terminal resistance of the device as a function of current through each field coil perform at 600 mK on sample 1. #### File: dATP2.0\_Again-18\_removed.dat **Description:** Four-terminal resistance of the device as a function of current through each field coil perform at 30 mK on sample 2. ## Code/software All data are visualized using Matplotlib and the numpy, scipy, plotly and pandas packages.