Thermally activated conductance in arrays of small Josephson junctions

TL;DR

This paper investigates how temperature influences conductance in arrays of small Josephson junctions, revealing thermally activated charge transport characterized by an activation energy related to the array's properties.

Contribution

It provides a detailed analysis of thermally activated conductance in Josephson junction arrays, highlighting the role of charge screening length and charging energy.

Findings

Zero-bias conductance follows thermally activated behavior

Activation energy scales with charge screening length and charging energy

Strong Coulomb blockade observed at low bias voltages

Abstract

We present measurements of the temperature-dependent conductance for series arrays of small-capacitance SQUIDs. At low bias voltages, the arrays exhibit a strong Coulomb blockade, which we study in detail as a function of temperature and Josephson energy $E_J$. We find that the zero-bias conductance is well described by thermally activated charge transport with the activation energy on the order of $\Lambda E_C$, where $\Lambda$ is the charge screening length in the array and $E_C$ is the charging energy of a single SQUID.