Conversion of electric current into heat involves microscopic processes that operate on nanometer length scales and release minute amounts of power. Although central to our understanding of the electrical properties of materials, individual mediators of energy dissipation have so far eluded direct observation. Using scanning nanothermometry with submicrokelvin sensitivity, we visualized and controlled phonon emission from individual atomic-scale 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. Rare in the bulk but abundant at graphene's edges, switchable atomic-scale phonon emitters provide the dominant dissipation mechanism. Our work offers insights for addressing key materials challenges in modern electronics and enables control of dissipation at the nanoscale.
Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
Imaging work and dissipation in the quantum Hall state in graphene.Nature. 2019 Nov;575(7784):628-633. doi: 10.1038/s41586-019-1704-3. Epub 2019 Oct 21. Nature. 2019. PMID: 31634903
Switching individual quantum dot emission through electrically controlling resonant energy transfer to graphene.Nano Lett. 2014 Dec 10;14(12):7115-9. doi: 10.1021/nl503587z. Epub 2014 Nov 19. Nano Lett. 2014. PMID: 25383700
Electrical switch to the resonant magneto-phonon effect in graphene.Nano Lett. 2014 Mar 12;14(3):1460-6. doi: 10.1021/nl404588g. Epub 2014 Feb 5. Nano Lett. 2014. PMID: 24490748
Energy Dissipation in Graphene Mechanical Resonators with and without Free Edges.Micromachines (Basel). 2016 Sep 5;7(9):158. doi: 10.3390/mi7090158. Micromachines (Basel). 2016. PMID: 30404329 Free PMC article. Review.
Atomic covalent functionalization of graphene.Acc Chem Res. 2013 Jan 15;46(1):77-86. doi: 10.1021/ar300143e. Epub 2012 Oct 2. Acc Chem Res. 2013. PMID: 23030800 Free PMC article. Review.
Cited by 1 article
Robust ferromagnetism in hydrogenated graphene mediated by spin-polarized pseudospin.Sci Rep. 2018 Sep 17;8(1):13940. doi: 10.1038/s41598-018-31934-0. Sci Rep. 2018. PMID: 30224827 Free PMC article.