On mesoscopic forces and quantized conductance in model metallic nanowires

TL;DR

This paper explores how electronic shell effects in metallic nanowires lead to stable configurations and quantized conductance, revealing oscillatory forces during structural transitions.

Contribution

It introduces a shell correction method to analyze energetics and conductance, highlighting the formation of magic wire configurations due to electronic quantization.

Findings

Identification of stable magic wire configurations

Correlation between energy oscillations and conductance steps

Quantization of conductance in units of 2e^2/h

Abstract

Energetics and conductance in jellium modelled nanowires are investigated using the local-density-functional-based shell correction method. In analogy with studies of other finite-size fermion systems, e.g., simple-metal clusters or He-3 clusters, we find that the energetics of the wire as a function of its radius (transverse reduced dimension) leads to formation of self-selecting magic wire configurations (MWC's, i.e., discrete sequence of wire radii with enhanced stability), originating from quantization of the electronic spectrum, namely formation of subbands which are the analogs of electronic shells in clusters. These variations in the energy result in oscillations in the force required to affect a transition from one MWC of the nanowire to another, and are correlated directly with step-wise variations of the quantized conductance of the nanowire in units of 2*e^2/h.