Screening and conductance relaxations in insulating granular aluminium thin films

TL;DR

This paper investigates conductance relaxations in insulating granular aluminium thin films, revealing a metallic-like screening effect that can be characterized by a temperature-dependent screening length, providing insights into the film's electronic properties.

Contribution

It introduces a new experimental method to measure conductance relaxation and screening length in granular aluminium films, highlighting a metallic-like screening phenomenon.

Findings

Conductance relaxation is insensitive to gate voltage changes.

Screening length varies with temperature.

Experimental details for measuring screening effects are provided.

Abstract

We have recently found in insulating granular Al thin film a new experimental feature (Delahaye et al., Phys. Rev. Lett. 106, 186602, 2011), namely the existence of a conductance relaxation that is not sensitive to gate voltage changes. This conductance relaxation is related to the existence of a metallic-like screening in the film and can be used to estimate its characteristic length scale. In the present paper, we give some experimental details on how this feature was measured and present our first results on the screening length temperature dependence.