Directional thermal channeling A phenomenon triggered by tight packing of heat sources

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 118; no. 40; pp. 1 - 6
• Main Authors: Honarvar, Hossein, Knobloch, Joshua L., Frazer, Travis D., Abad, Begoña, McBennett, Brendan, Hussein, Mahmoud I., Kapteyn, Henry C., Murnane, Margaret M., Hernandez-Charpak, Jorge N.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05-10-2021
• Subjects: Channeling; Cooling; Heat; Heat sources; Materials science; Nanoelectronics; Phonons; Physical Sciences; Quantum sensors; Scattering; Substrates; Transport phenomena; Transport properties; molecular dynamics; thermal channeling; nanoscale heat sources; nanoscale thermal transport; phonon transport
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2109056118

Understanding nanoscale thermal transport is critical for nanoengineered devices such as quantum sensors, thermoelectrics, and nanoelectronics. However, despite overwhelming experimental evidence for nondiffusive heat dissipation from nanoscale heat sources, the underlying mechanisms are still not understood. In this work, we show that for nanoscale heat source spacings that are below the mean free path of the dominant phonons in a substrate, close packing of the heat sources increases in-plane scattering and enhances cross-plane thermal conduction. This leads to directional channeling of thermal transport—a novel phenomenon. By using advanced atomic-level simulations to accurately access the lattice temperature and the phonon scattering and transport properties, we finally explain the counterintuitive experimental observations of enhanced cooling for close-packed heat sources. This represents a distinct fundamental behavior in materials science with far-reaching implications for electronics and future quantum devices.