Electrical transport properties of ultrathin disordered films

TL;DR

This study investigates how disorder, substrate properties, and quantum size effects influence electrical transport and superconductivity in ultrathin bismuth films quenched at low temperatures.

Contribution

It provides experimental insights into the interplay of localization and superconductivity in ultrathin Bi films, highlighting the role of substrate dielectric constant and quantum size effects.

Findings

Transport properties depend on substrate dielectric constant.

Quantum size effects influence film structure and transport.

Disorder and substrate interactions affect superconductivity.

Abstract

We report an experimental study of quench condensed ($2K\le T \le 15K$) disordered ultrathin films of {\rm Bi} where localisation effects and superconductivity compete. Experiments are done with different substrates and/or different underlayers. Quasi-free standing films of {\rm Bi}, prepared by quenching {\rm Bi} vapours onto solid {\rm Xe}, are also studied. The results show a dependence of the transport properties both on the dielectric constant of the substrate/underlayer as well as the temperature of quench condensation. RHEED studies indicate that quantum size effects are important in these systems. In this paper, we try to correlate the structure of the films to the transport properties obtained.