Resonant heating and substrate-mediated cooling of a single C60 molecule in a tunnel junction

TL;DR

This study investigates how different metallic substrates affect heating and cooling of a single C60 molecule in a tunnel junction, revealing substrate-dependent thermal stability and energy dissipation mechanisms.

Contribution

It demonstrates how substrate choice influences electron-induced heating and vibrational quenching in single-molecule junctions, highlighting the role of charge transfer.

Findings

Thermal decomposition power varies significantly across substrates.

Charge transfer correlates with molecular vibrational quenching.

Resonance structures influence heating and stability.

Abstract

We study the influence of different metallic substrates on the electron induced heating and heat dissipation of single C60 molecules in the junction of a low temperature scanning tunneling microscope. The electron current passing through the molecule produces a large amount of heat due to electron-phonon coupling, eventually leading to thermal decomposition of the fullerene cage. The power for decomposition varies with electron energy and reflects the resonance structure participating in the transport. The average value for thermal decomposition of C60 on Cu(110) amounts to 21 $\mu$W, while it is much lower on Pb(111) (2.9 $\mu$W) and on Au(111) (1.0 $\mu$W). We ascribe this difference to the amount of charge transfer into C60 upon adsorption on the different surfaces, which facilitates molecular vibron quenching by electron-hole pair creation.