Strange effect of disorder on electron transport through a thin film

TL;DR

This paper investigates how varying impurity density affects electron transport in a thin film, revealing an unusual increase in current with disorder strength in the strong disorder regime, contrary to typical behavior.

Contribution

It introduces a model showing the counterintuitive effect of disorder on electron transport in thin films with impurity gradients, highlighting finite size influences.

Findings

Current amplitude increases with disorder in strong disorder regime

Transport behavior is opposite to conventional disordered systems

Finite size significantly affects electron transport

Abstract

A novel feature of electron transport is explored through a thin film of varying impurity density with the distance from its surface. The film, attached to two metallic electrodes, is described by simple tight-binding model and its coupling to the electrodes is treated through Newns-Anderson chemisorption theory. Quite interestingly it is observed that, in the strong disorder regime the amplitude of the current passing through the film increases with the increase of the disorder strength, while it decreases in the weak disorder regime. This anomalous behavior is completely opposite to that of conventional disordered systems. Our results also predict that the electron transport is significantly influenced by the finite size of the thin film.