Eur. Phys. J. B (2013) 86: 184
https://doi.org/10.1140/epjb/e2013-30583-8

Regular Article

Quantum transmission across a low-dimensional nanoscale diffuse junction

Physique de la Matière Condensée, École Polytechnique-CNRS, 91128 Palaiseau, France

^a e-mail: francois.devreux@polytechnique.fr

Received: 12 July 2012
Received in final form: 19 December 2012
Published online: 24 April 2013

Abstract

The transmission across a nano-scale diffuse junction between two metals is studied numerically for 1D wires and 2D ribbons within a tight-binding model. In such a situation, a junction electric potential must appear to equilibrate the electrochemical potential on each side of the junction. We compute the transmission under two very different potential distributions and we find that the typical transmission does not depend on the details of this distribution. The transmission is found to follow a scaling law. The variations of the 1D transmission are explained in a semi-classical way by considering the multiple reflections caused by the barriers due to the on-site energy mismatch between the two metals. Both the 1D and 2D results can also be partly interpreted in the frame of the Anderson theory of localisation.