InAs nanowire superconducting tunnel junctions: spectroscopy, thermometry and nanorefrigeration

Abstract

We demonstrate an original method -- based on controlled oxidation -- to create high-quality tunnel junctions between superconducting Al reservoirs and InAs semiconductor nanowires. We show clean tunnel characteristics with a current suppression by over $4$ orders of magnitude for a junction bias well below the Al gap ${\Delta }_0\approx 200\mu \mathrm{eV}$. The experimental data are in close agreement with the BCS theoretical expectations of a superconducting tunnel junction. The studied devices combine small-scale tunnel contacts working as thermometers as well as larger electrodes that provide a proof-of-principle active {\em cooling} of the electron distribution in the nanowire. A peak refrigeration of about $\delta T=10\mathrm{mK}$ is achieved at a bath temperature $T_{bath}\approx 250-350\mathrm{mK}$ in our prototype devices. This method opens important perspectives for the investigation of thermoelectric effects in semiconductor nanostructures and for nanoscale refrigeration.

6 pages, 4 color figures

References in corpus (10)

• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Tunable Supercurrent Through Semiconductor Nanowires
• The Josephson heat interferometer
• Rectification of electronic heat current by a hybrid thermal diode
• Micrometre-scale refrigerators
• Ultrasensitive Proximity Josephson Sensor with Kinetic Inductance Read-Out
• InAs nanowire hot-electron Josephson transistor
• Local noise in a diffusive conductor
• Cooling electrons from 1 K to 400 mK with V-based nanorefrigerators
• Sub-micron normal-metal/insulator/superconductor tunnel junction thermometer and cooler using Nb

Cited by in corpus (8)

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• Nonlocal thermoelectricity in a Cooper-pair splitter
• Correlation-induced refrigeration with superconducting single-electron transistors
• Quantum-enhanced performance in superconducting Andreev-reflection engines
• Thermoelectric processes of quantum normal-superconductor interfaces
• Electrical and thermal transport through $\alpha -T_3$ NIS junction
• Thermopower generation and thermoelectric cooling in a Kane-Mele normal-insulator-superconductor nano-junction
• Active electron cooling of graphene