Data from: Mapping the topological proximity-induced gap in multiterminal Josephson junctions
Data files
Nov 20, 2024 version files 6.95 MB
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dATP2.0_300mK.dat
1.97 MB
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dATP2.0_Again-18_removed.dat
1.97 MB
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dATPZeta_No1-16.dat
55.66 KB
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dATPZeta_No1-20.dat
57.43 KB
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dATPZeta_No1-6.dat
112.02 KB
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modified_dATPZeta_No1-42.dat
2.78 MB
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README.md
2.72 KB
Abstract
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.
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.
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.