Manipulation of organic polyradicals in a single-molecule transistor

TL;DR

This study demonstrates electric control of magnetic states in a single organic molecule using a three-terminal device, revealing tunable ferromagnetic and antiferromagnetic interactions with potential for organic molecular magnetism.

Contribution

It introduces a method to reversibly switch the magnetic states of a single organic molecule via electrochemical gating, supported by a theoretical Heisenberg model and valence bond analysis.

Findings

Reversible switching between three redox states.

Observation of both ferromagnetic and antiferromagnetic couplings.

Effective low-energy Heisenberg model captures the magnetic behavior.

Abstract

Inspired by cotunneling spectroscopy of spin-states in a single OPE5-based molecule, we investigate the prospects for electric control of magnetism in purely organic molecules contacted in a three-terminal geometry. Using the gate electrode, the molecule is reversibly switched between three different redox states, with magnetic spectra revealing both ferromagnetic and antiferromagnetic exchange couplings on the molecule. These observations are shown to be captured by an effective low-energy Heisenberg model, which we substantiate microscopically by a simple valence bond description of the molecule. These preliminary findings suggest an interesting route towards functionalized all-organic molecular magnetism.