Effect of the electromagnetic environment on arrays of small normal metal tunnel junctions: Numerical and experimental investigation

TL;DR

This study investigates how the external electromagnetic environment affects tunneling in small metal junction arrays, revealing that the environment's influence diminishes with more junctions and identifying a specific impedance where conductance features are maximized.

Contribution

The paper provides new analytical formulas based on phase-correlation theory and combines numerical and experimental results to understand environmental effects on tunneling in junction arrays.

Findings

Environmental influence decreases with more junctions

Maximum conductance dip occurs at ~5 kΩ impedance

Analytical formulas align with experimental data

Abstract

We present results of a set of experiments to investigate the effect of dissipative external electromagnetic environment on tunneling in linear arrays of junctions in the weak tunneling regime. The influence of this resistance decreases as the number of junctions in the chain increases and ultimately becomes negligible. Further, there is a value of external impedance, typically \~5 k$\Omega$, at which the half-width of the zero-voltage dip in the conductance curve shows a maximum. Some new analytical formulae, based on the phase-correlation theory, along with numerical results will be presented.