Graded thermal conductivity in 2D and 3D homogeneous hotspot systems. (January 2022)

• Record Type: Journal Article
• Authors: Zhang, Chuang; Ma, Dengke; Shang, Manyu; Wan, Xiao; Lü, Jing-Tao; Guo, Zhaoli; Li, Baowen; Yang, Nuo
• Is Part Of: Materials today physics. Volume 22(2022)
• Publication Date: 2022-01
• Subjects: Hydrodynamic/ballistic phonon transport -- Anomalous heat diffusion -- Boltzmann transport equation -- Non-Fourier heat conduction; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2022.100605
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: Hotspot is a ubiquitous phenomenon in micro/nanoscale chips. Here, it is found that the thermal conductivity is not a constant in such a homogeneous system. The hotspots in homogeneous 2D disk/3D sphere and graphene disk are studied based on phonon Boltzmann transport equation. Instead a constant value, a graded thermal conductivity is observed even if the system size is fixed. The mechanisms of phonon scattering are analyzed. It is found that for a system with fixed size, the graded thermal conductivity is predictable as long as there is not sufficient phonon scattering, which is independent on material properties, dimensions or system size. This work may shed light on both theoretical and experimental studies on heat dissipation. Graphical abstract: Image 1 Highlights: It demonstrates a fundamental physical understanding of thermal transport of hotspots. Hotspots in a 2D disk, 3D ball, and graphene disk (up to 20 μm) are studied by phonon Boltzmann transport equation. It is found that the thermal conductivity is graded diverging from the hotspot to the outer, which is much different from conventional understanding. The graded thermal conductivity comes from insufficient phonon scatterings, which are independent of the material, dimension, or system size.