Ballistic Phonons in Ultrathin Nanowires
Vakulov, Daniel (Eindhoven University of Technology)
Gireesan, Subash (Center for Computational Energy Research)
Swinkels, Milo Y. (University of Basel)
Chavez, Ruben (Eindhoven University of Technology)
Vogelaar, Tom (Eindhoven University of Technology)
Torres, Pol (Universitat Autònoma de Barcelona. Departament de Física)
Campo, Alessio (University of Basel)
De Luca, Marta (University of Basel)
Verheijen, Marcel A. (Eindhoven University of Technology)
Koelling, Sebastian (Eindhoven University of Technology)
Gagliano, Luca (Eindhoven University of Technology)
Haverkort, Jos E. M. (Eindhoven University of Technology)
Àlvarez Calafell, Francesc Xavier (Universitat Autònoma de Barcelona)
Bobbert, Peter A. (Center for Computational Energy Research)
Zardo, Ilaria (University of Basel)
Bakkers, Erik P. A. M. (Eindhoven University of Technology)

Data:	2020
Resum:	According to Fourier's law, a temperature difference across a material results in a linear temperature profile and a thermal conductance that decreases inversely proportional to the system length. These are the hallmarks of diffusive heat flow. Here, we report heat flow in ultrathin (25 nm) GaP nanowires in the absence of a temperature gradient within the wire and find that the heat conductance is independent of wire length. These observations deviate from Fourier's law and are direct proof of ballistic heat flow, persisting for wire lengths up to at least 15 μm at room temperature. When doubling the wire diameter, a remarkably sudden transition to diffusive heat flow is observed. The ballistic heat flow in the ultrathin wires can be modeled within Landauer's formalism by ballistic phonons with an extraordinarily long mean free path.
Ajuts:	European Commission 617256 European Commission 756365 Ministerio de Ciencia e Innovación RTI2018-097876-B-C21
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Nanowires ; GaP ; Heat transport ; Ballistic phonons ; Raman spectroscopy
Publicat a:	Nano letters, Vol. 20, Num. 4 (April 2020) , p. 2703-2709, ISSN 1530-6992

DOI: 10.1021/acs.nanolett.0c00320
PMID: 32091910

7 p, 6.2 MB

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