Tuning the Kondo effect with a mechanically controllable break junction

TL;DR

This paper demonstrates how mechanically adjusting a break junction can control the Kondo effect in C60 molecules, affecting resonance properties and revealing insights into electron transport in molecular systems.

Contribution

It introduces a method to tune the Kondo effect in molecular junctions via mechanical control, showing direct manipulation of Kondo resonance characteristics.

Findings

Kondo resonance width and height are tunable by electrode spacing.

The conductance follows the expected scaling for the spin-1/2 Kondo effect.

Finite-bias Kondo features relate to molecular vibrational modes.

Abstract

We study electron transport through C60 molecules in the Kondo regime using a mechanically controllable break junction. By varying the electrode spacing, we are able to change both the width and height of the Kondo resonance, indicating modification of the Kondo temperature and the relative strength of coupling to the two electrodes. The linear conductance as a function of T/T_K agrees with the scaling function expected for the spin-1/2 Kondo problem. We are also able to tune finite-bias Kondo features which appear at the energy of the first C60 intracage vibrational mode.