Differential Conductance Measurements of MgB2-Based Josephson Junctions Below 1 Kelvin

TL;DR

This study presents low-temperature differential conductance measurements of MgB2-based Josephson junctions below 1 Kelvin, revealing detailed insights into the sigma- and pi-band gaps consistent with theoretical models.

Contribution

First low-temperature (below 1 Kelvin) measurements of MgB2 Josephson junctions, providing new experimental data on band gap structures.

Findings

Observation of sigma- and pi-band gap features in conductance data

Confirmation of theoretical predictions regarding band structure

Enhanced understanding of MgB2 junction behavior at ultra-low temperatures

Abstract

Magnesium diboride has many intriguing characteristics, including its relatively high critical temperature and two-band nature. Most prior studies of MgB2 thin film Josephson junctions have been conducted above 2 Kelvin. We report results of sub-1 Kelvin experiments of MgB2/insulator/Pb junctions whose a-b plane is exposed for electron tunneling. By measuring differential conductance at low temperature, new details in the structure of the sigma- and pi-band gaps are observed in this data, consistent with theoretical predictions.