Nano Research

Article Title

InAs nanowire superconducting tunnel junctions: Quasiparticle spectroscopy, thermometry, and nanorefrigeration


InAs nanowire, superconducting tunnel junction, thermometry, nanorefrigeration


ABSTRACT We demonstrate an original method based on controlled oxidation for creating high-quality tunnel junctions between superconducting Al reservoirs and InAs semiconductor nanowires (NWs). We show clean tunnel characteristics with a current suppression by >4 orders of magnitude for a junction bias well below the Al gap of Δ0 ≈ 200 μeV. The experimental data agree well with the Bardeen– Cooper–Schrieffer theoretical expectations for a superconducting tunnel junction. The studied devices employ small-scale tunnel contacts functioning as thermometers as well as larger electrodes that provide proof-of-principle active cooling of the electron distribution in the NWs. A peak refrigeration of approximately δT = 10 mK is achieved at a bath temperature of Tbath ≈ 250–350 mK for our prototype devices. This method introduces important perspectives for the investigation of the thermoelectric effects in semiconductor nanostructures and for nanoscale refrigeration.

Graphical Abstract


Tsinghua University Press