Imaging resonant dissipation from individual atomic defects in graphene

摘要

Conversion of electric current into heat involves microscopic processes thatoperate on nanometer length-scales and release minute amounts of power. Whilecentral to our understanding of the electrical properties of materials,individual mediators of energy dissipation have so far eluded directobservation. Using scanning nano-thermometry with sub-micro K sensitivity wevisualize and control phonon emission from individual atomic defects ingraphene. The inferred electron-phonon 'cooling power spectrum' exhibits sharppeaks when the Fermi level comes into resonance with electronic quasi-boundstates at such defects, a hitherto uncharted process. Rare in the bulk butabundant at graphene's edges, switchable atomic-scale phonon emitters definethe dominant dissipation mechanism. Our work offers new insights for addressingkey materials challenges in modern electronics and engineering dissipation atthe nanoscale.