Thermal Dispersion Metrics and Phonon Wavepacket Scattering across Silicon-Diamond Heterojunctions

International Journal of Physics | Vol. 10, No. 4, April 2019 | pp. 25–32

DOI: 10.46882/2019/IJP/000108

Research Article

Title: Thermal Dispersion Metrics and Phonon Wavepacket Scattering across Silicon-Diamond Heterojunctions

Names of Authors: D. W. Meyer¹, H. L. Mueller²

Authors’ Affiliations: ¹Institute of Physics, Karlsruher Institut für Technologie, Karlsruhe, Germany; ²Institut für Kernphysik, Karlsruher Institut für Technologie, Karlsruhe, Germany

Abstract: Dissipating intense localized heat across structural material boundaries is a significant challenge in modern wide-bandgap high-frequency nanoelectronics and high-power radar modules. This paper utilizes molecular dynamics simulations to quantify thermal dispersion metrics and track acoustic phonon wavepacket scattering at mismatched silicon-diamond (Si-C) heterojunctions. We constructed atomistic models using the optimized Tersoff empirical potentials, incorporating varying concentrations of interfacial dislocation defects and interfacial chemical grading configurations. Longitudinal and transverse acoustic phonon wavepackets were generated with narrow frequency spreads centered between 3.0 THz and 12.0 THz. The computational data demonstrate that high-frequency acoustic phonons (f greater than 6.5 THz) undergo strong diffuse scattering at the rough interface, dropping the transmission coefficient from 0.72 down to 0.14. This transport degradation is driven by severe acoustic impedance mismatch and localized interface vibrational modes. The overall interfacial thermal conductance was calculated to decrease by 48.0% when the interface defect density scaled from 1.0% to 5.0% at 300.0 K. These molecular dynamics calculations clarify the atomic-scale paths limiting heat carrier propagation, helping engineers design targeted thermal management interfaces for high-power electronics.

Keywords: Thermal conductance; phonon wavepacket; molecular dynamics; interface defects; silicon-diamond; nanoelectronics

Manuscript Timeline: Received: January 08, 2019; Revised: February 17, 2019; Accepted: March 09, 2019; Published: April 10, 2019

Citation: Meyer, D. W., & Mueller, H. L. (2019). Thermal Dispersion Metrics and Phonon Wavepacket Scattering across Silicon-Diamond Heterojunctions. International Journal of Physics, 10(4), 25–32.

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