Resonant electron heating and molecular phonon cooling in single C$_{60}$ junctions

TL;DR

This study investigates how a single C60 molecule in an STM junction heats up and cools down due to electron interactions, revealing the role of molecular resonances and contact formation in heat dissipation.

Contribution

It demonstrates the impact of resonant electron-phonon coupling and contact-induced vibrational decay on molecular heating and cooling in single-molecule junctions.

Findings

Decomposition power depends on electron energy and molecular resonance.

Contact with STM tip allows the molecule to sustain larger currents.

Transport simulations confirm resonant heating and vibrational cooling mechanisms.

Abstract

We study heating and heat dissipation of a single \c60 molecule in the junction of a scanning tunneling microscope (STM) by measuring the electron current required to thermally decompose the fullerene cage. The power for decomposition varies with electron energy and reflects the molecular resonance structure. When the STM tip contacts the fullerene the molecule can sustain much larger currents. Transport simulations explain these effects by molecular heating due to resonant electron-phonon coupling and molecular cooling by vibrational decay into the tip upon contact formation.