Imaging resonant dissipation from individual atomic defects in graphene

TL;DR

This study visualizes and controls phonon emission from individual atomic defects in graphene, revealing resonant dissipation processes at the nanoscale crucial for understanding electronic heat management.

Contribution

It introduces a novel scanning nano-thermometry technique to directly observe atomic-scale phonon emission and dissipation mechanisms in graphene defects.

Findings

Resonant peaks in electron-phonon cooling power spectrum at defect sites.

Atomic-scale phonon emitters are abundant at graphene edges.

Switchable phonon emission defines dominant dissipation pathways.

Abstract

Conversion of electric current into heat involves microscopic processes that operate on nanometer length-scales and release minute amounts of power. While central to our understanding of the electrical properties of materials, individual mediators of energy dissipation have so far eluded direct observation. Using scanning nano-thermometry with sub-micro K sensitivity we visualize and control phonon emission from individual atomic defects in graphene. The inferred electron-phonon 'cooling power spectrum' exhibits sharp peaks when the Fermi level comes into resonance with electronic quasi-bound states at such defects, a hitherto uncharted process. Rare in the bulk but abundant at graphene's edges, switchable atomic-scale phonon emitters define the dominant dissipation mechanism. Our work offers new insights for addressing key materials challenges in modern electronics and engineering dissipation at the nanoscale.