Sequential Tunneling through Molecular Spin Rings

TL;DR

This paper investigates electron transport in molecules with ring-structured spins, revealing how spin interactions and contact sites influence conductance, including potential zero-bias suppression.

Contribution

It introduces a model linking spin configurations to transport properties in molecular rings with anisotropy, highlighting contact-site effects.

Findings

Contact-site dependence significantly affects current flow.

Antiferromagnetic coupling can suppress zero-bias conductance.

Transport properties are linked to the spin structure via Zener double-exchange.

Abstract

We consider electrical transport through molecules with Heisenberg-coupled spins arranged in a ring structure in the presence of an easy-axis anisotropy. The molecules are coupled to two metallic leads and a gate. In the charged state of the ring, a Zener double-exchange mechanism links transport properties to the underlying spin structure. This leads to a remarkable contact-site dependence of the current, which for an antiferromagnetic coupling of the spins can lead to a total suppression of the zero-bias conductance when the molecule is contacted at adjacent sites.