Probing the Orbital Origin of Conductance Oscillations in Atomic Chains

TL;DR

This study reveals that conductance oscillations in atomic chains are driven by changes in orbital hybridization related to atomic configuration, providing insights into controlling nanoscale conductance through orbital engineering.

Contribution

The paper uncovers the orbital origin of conductance oscillations in atomic chains and links structural transitions to electronic structure variations, advancing understanding of atomic-scale conductance.

Findings

Oscillations are linked to conduction channel variations during structural transitions.

Hybridization between atomic orbitals causes conductance oscillations.

Directional orbital interactions influence conductance sensitivity.

Abstract

We investigate periodical oscillations in the conductance of suspended Au and Pt atomic chains during elongation under mechanical stress. Analysis of conductance and shot noise measurements reveals that the oscillations are mainly related to variations in a specific conduction channel as the chain undergoes transitions between zigzag and linear atomic configurations. The calculated local electronic structure shows that the oscillations originate from varying degrees of hybridization between the atomic orbitals along the chain as a function of the zigzag angle. These variations are highly dependent on the directionality and symmetry of the relevant orbitals, in agreement with the order-of-magnitude difference between the Pt and Au oscillation amplitudes observed in experiment. Our results demonstrate that the sensitivity of conductance to structural variations can be controlled by designing atomic-scale conductors in view of the directional interactions between atomic orbitals.