Subkelvin tunneling spectroscopy showing Bardeen-Cooper-Schrieffer superconductivity in heavily boron-doped silicon epilayers

TL;DR

This study used subkelvin tunneling spectroscopy to demonstrate BCS-type superconductivity in heavily boron-doped silicon epilayers, supporting phonon-mediated hole pairing.

Contribution

It provides direct spectroscopic evidence of BCS superconductivity in boron-doped silicon, confirming the phonon-mediated pairing mechanism in this material.

Findings

Superconducting gap follows BCS temperature dependence

Spectral shape consistent with homogeneous superconductor

Energy gap dispersion within +/- 10%

Abstract

Scanning tunneling spectroscopies in the subKelvin temperature range were performed on superconducting Silicon epilayers doped with Boron in the atomic percent range. The resulting local differential conductance behaved as expected for a homogeneous superconductor, with an energy gap dispersion below +/- 10%. The spectral shape, the amplitude and temperature dependence of the superconductivity gap follow the BCS model, bringing further support to the hypothesis of a hole pairing mechanism mediated by phonons in the weak coupling limit.