In this article, we show how relativistic α-stable processes can be used to explain quasiballistic heat conduction in semiconductors. This is a method that can fit experimental results of ultrafast laser heating in alloys. It also provides a connection to a rich literature on the Feynman-Kac formalism and random processes that transition from a stable Lévy process on short time and length scales to the Brownian motion at larger scales. This transition was captured by a heuristic truncated Lévy distribution in earlier papers. The rigorous Feynman-Kac approach is used to derive sharp bounds for the transition kernel. Future directions are briefly discussed.
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http://dx.doi.org/10.1103/PhysRevE.101.042110 | DOI Listing |
ACS Nano
April 2024
Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
Nanostructured semiconductors promise functional thermal management for microelectronics and thermoelectrics through a rich design capability. However, experimental studies on anisotropic in-plane thermal conduction remain limited, despite the demand for directional heat dissipation. Here, inspired by an oriental wave pattern, a periodic network of bent wires, we investigate anisotropic in-plane thermal conduction in nanoscale silicon phononic crystals with the thermally dead volume.
View Article and Find Full Text PDFPhys Rev E
July 2022
Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Transient heat dissipation in close-packed quasi-two-dimensional nanoline and three-dimensional nanocuboid hotspot systems is studied based on the phonon Boltzmann transport equation. It is found that, counterintuitively, the heat dissipation efficiency is not a monotonic function of the distance between adjacent nanoscale heat sources but reaches the highest value when this distance is comparable to the phonon mean free path. This is due to the competition of two thermal transport processes: quasiballistic transport when phonons escape from the nanoscale heat source and the scattering among phonons originating from the adjacent nanoscale heat source.
View Article and Find Full Text PDFPhys Rev E
May 2022
Peter the Great Saint Petersburg Polytechnical University, Saint Petersburg, Russia.
We investigate the unsteady heat (energy) transport in an infinite mass-in-mass chain with a given initial temperature profile. The chain consists of two sublattices: the β-Fermi-Pasta-Ulam-Tsingou (FPUT) chain and oscillators (of a different mass) connected to each FPUT particle. Initial conditions are such that initial kinetic temperatures of the FPUT particles and the oscillators are equal.
View Article and Find Full Text PDFACS Nano
December 2021
Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States.
Layering two-dimensional van der Waals materials provides a high degree of control over atomic placement, which could enable tailoring of vibrational spectra and heat flow at the sub-nanometer scale. Here, using spatially resolved ultrafast thermoreflectance and spectroscopy, we uncover the design rules governing cross-plane heat transport in superlattices assembled from monolayers of graphene (G) and MoS (M). Using a combinatorial experimental approach, we probe nine different stacking sequences, G, GG, MG, GGG, GMG, GGMG, GMGG, GMMG, and GMGMG, and identify the effects of vibrational mismatch, interlayer adhesion, and junction asymmetry on thermal transport.
View Article and Find Full Text PDFNanomaterials (Basel)
October 2020
Department of Mechanical Engineering, College of Electrical and Mechanical Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan.
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