Spin-coupled double-quantum-dot behavior inside a single-molecule transistor

TL;DR

This paper reports the observation of Kondo and split Kondo peaks in a single-molecule transistor exhibiting double quantum dot behavior, revealing complex spin interactions and electron charging effects.

Contribution

It demonstrates molecular double quantum dot behavior and Kondo peak splitting due to spin transitions within a single-molecule transistor.

Findings

Observation of Kondo and split Kondo peaks

Double quantum dot behavior in a molecular system

Kondo peak splitting induced by gate voltage

Abstract

We report on the observation of Kondo and split Kondo peaks in single-molecule transistors containing a single spin transition molecule with a Fe2+ ion. Coulomb blockade characteristics reveal a double quantum dot behavior in a parallel configuration, making our system a molecular equivalent to a semiconducting double-quantum-dot system. As the gate voltage is increased the charging of the second dot by an additional electron induces a splitting of the Kondo peak. We discuss possible origins of this effect including a spin transition into a high-spin state.