Atomistic evidence of hydrodynamic heat transfer in nanowires

Paul Desmarchelier (1, 2) , Albert Beardo (3) , F. Xavier Alvarez (3) , Anne Tanguy (4, 5) , Konstantinos Termentzidis (1, 2)

1 CETHIL - Centre d'Energétique et de Thermique de Lyon
2 CNRS - Centre National de la Recherche Scientifique
3 UAB - Universitat Autònoma de Barcelona = Autonomous University of Barcelona = Universidad Autónoma de Barcelona
4 ONERA, Université Paris Saclay [Palaiseau]
5 LaMCoS - Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne]

With wave-packet propagation simulations and heat flux estimation via molecular dynamics, we show that the heat flux radial distribution in silicon nanowires can be described by a mesoscopic model, the hydrodynamic heat equation. We observe Poiseuille like heat flux profile, that cannot be described by a simple kinetic model such as the Fuchs-Sondheimer model, in both pristine and core/shell nanowires. The addition of a shell does not change the shape of the radial heat flux distribution, but just modifies the maximum of the heat flux in the center of the nanowire. These results show that there is a heat flux depletion length for pristine or core shell nanowires, 1-2 nm away from the boundary of the crystalline part. The parameters of the mesoscopic model are discussed in terms of microscopic properties, including the phonon mean free path as function of frequency and the partial vibrational density of states in the different regions of the nanowire.

Mots clés: hydrodynamic heat transport; Nanowires; Amorphous Shell; Nanocomposites

Domaines: Matériaux; Micro et nanotechnologies/Microélectronique; Thermique [physics.class-ph]

Paul Desmarchelier, Albert Beardo, F. Xavier Alvarez, Anne Tanguy, Konstantinos Termentzidis. Atomistic evidence of hydrodynamic heat transfer in nanowires. International Journal of Heat and Mass Transfer, 2022, 194, pp.123003. ⟨10.1016/j.ijheatmasstransfer.2022.123003⟩. ⟨hal-03690617⟩