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Pàgina inicial > Articles > Articles publicats > Observation of giant and tunable thermal diffusivity of a Dirac fluid at room temperature |
Data: | 2021 |
Resum: | Conducting materials typically exhibit either diffusive or ballistic charge transport. When electron-electron interactions dominate, a hydrodynamic regime with viscous charge flow emerges -. More stringent conditions eventually yield a quantum-critical Dirac-fluid regime, where electronic heat can flow more efficiently than charge -. However, observing and controlling the flow of electronic heat in the hydrodynamic regime at room temperature has so far remained elusive. Here we observe heat transport in graphene in the diffusive and hydrodynamic regimes, and report a controllable transition to the Dirac-fluid regime at room temperature, using carrier temperature and carrier density as control knobs. We introduce the technique of spatiotemporal thermoelectric microscopy with femtosecond temporal and nanometre spatial resolution, which allows for tracking electronic heat spreading. In the diffusive regime, we find a thermal diffusivity of roughly 2,000 cm 2 s −1, consistent with charge transport. Moreover, within the hydrodynamic time window before momentum relaxation, we observe heat spreading corresponding to a giant diffusivity up to 70,000 cm 2 s −1, indicative of a Dirac fluid. Our results offer the possibility of further exploration of these interesting physical phenomena and their potential applications in nanoscale thermal management. Spatiotemporal thermoelectric microscopy enables the observation of electronic heat flow in graphene in diffusive and hydrodynamic regimes at room temperature, as well as a controlled transition from a Fermi liquid to Dirac fluid. |
Ajuts: | European Commission 881603 European Commission 873028 European Commission 804349 European Commission 785219 European Commission 670949 Ministerio de Economía y Competitividad CEX-2019-000910-S Ministerio de Economía y Competitividad PID2019-111673GB-I00 Ministerio de Economía y Competitividad RTI2018-099957-J-I00 Ministerio de Economía y Competitividad PGC2018-096875-B-I00 Ministerio de Economía y Competitividad RYC-2017-22330 Ministerio de Economía y Competitividad SEV-2017-0706 Ministerio de Economía y Competitividad BES-2016-078727 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1369 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1656 |
Drets: | Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original. |
Llengua: | Anglès |
Document: | Article ; recerca ; Versió publicada |
Matèria: | Graphene ; Electronic properties and materials ; Ultrafast photonics |
Publicat a: | Nature Nanotechnology, Vol. 16 (Nov. 2021) , p. 1195-1200, ISSN 1748-3395 |
13 p, 3.8 MB |