Electrostatic Control over Temperature-Dependent Tunneling across a Single Molecule Junction

TL;DR

This study investigates how temperature influences charge transport in a single ferrocene-based molecule, revealing complex dependencies on gate voltage and providing insights into tunneling mechanisms in molecular electronics.

Contribution

It provides a detailed experimental analysis of temperature effects on a single molecule's tunneling behavior, supported by a theoretical model, advancing understanding of molecular charge transport.

Findings

Current exponentially increases in Coulomb blockade regime with temperature

Current decreases at charge degeneracy points as temperature rises

Transport remains temperature-independent at resonance

Abstract

Understanding how the mechanism of charge transport through molecular tunnel junctions depends on temperature is crucial to control electronic function in molecular electronic devices. With just a few systems investigated as a function of bias and temperature so far, thermal effects in molecular tunnel junctions remain poorly understood. Here we report a detailed charge transport study of an individual redox-active ferrocene-based molecule over a wide range of temperatures and applied potentials. The results show the temperature dependence of the current to vary strongly as a function of the gate voltage. Specifically, the current across the molecule exponentially increases in the Coulomb blockade regime and decreases at the charge degeneracy points, while remaining temperature-independent at resonance. Our observations can be well accounted for by a formal single-level tunneling model where the temperature dependence relies on the thermal broadening of the Fermi distributions of the electrons in the leads.