Ballistic phonons in ultrathin nanowires

Vakulov, Daniel and Gireesan, Subash and Swinkels, Milo Y. and Chavez, Ruben and Vogelaar, Tom J. and Torres, Pol and Campo, Alessio and De Luca, Marta and Verheijen, Marcel A. and Koelling, Sebastian and Gagliano, Luca and Haverkort, Jos E. M. and Alvarez, F. Xavier and Bobbert, Peter A. and Zardo, Ilaria and Bakkers, Erik P. A. M.. (2020) Ballistic phonons in ultrathin nanowires. Nano Letters, 20 (4). pp. 2703-2709.

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Official URL: https://edoc.unibas.ch/79562/

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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.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Experimental Material Physics (Zardo)
UniBasel Contributors:Zardo, Ilaria and Swinkels, Milo Yaro and De Luca, Marta and Campo, Alessio
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Chemical Society
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:29 Apr 2021 12:16
Deposited On:29 Apr 2021 12:16

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