Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Silicide Core-Shell Nanowire Interfaces

International Journal of Physics | Vol. 15, No. 5, May 2024 | pp. 33–40

DOI: 10.46882/2024/IJP/000169

Research Article

Title: Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Silicide Core-Shell Nanowire Interfaces

Names of Authors: M. G. Richter¹, D. W. Meyer²

Authors’ Affiliations:
¹ Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
² Institute of Physics, Karlsruher Institut für Technologie, Karlsruhe, Germany

Abstract: Restricting cross-interface thermal transport across mismatched semiconductor boundaries is a primary technical challenge when engineering next-generation high-efficiency thermoelectric harvesters and protecting microcircuit nodes from hotspot deterioration. This paper uses molecular dynamics simulations to quantify thermal dispersion metrics and track phonon wavepacket scattering at defective silicon-silicide (Si-NiSi2) core-shell nanowire boundaries. We constructed atomistic structural configurations using the optimized Stillinger-Weber empirical potentials, incorporating varying concentrations of interfacial point defects and shell thickness variations. Longitudinal and transverse acoustic phonon wavepackets were launched with narrow frequency spreads centered between 2.0 THz and 8.0 THz. The computational data demonstrate that high-frequency acoustic phonons (f greater than 5.2 THz) undergo strong diffuse scattering at the rough interface, dropping the calculated transmission coefficient from 0.84 down to 0.20. This transport degradation is driven by localized strain fields and interface-bound vibrational modes. The overall interfacial thermal conductance decreased by 50.0% when the interface roughness parameter scaled from 0.1 nm to 0.6 nm at 300.0 K, revealing structural constraints for nanoscale device design.

Keywords: Thermal dispersion; phonon wavepacket; molecular dynamics; core-shell nanowires; thermoelectric cooling; silicide interfaces

Manuscript Timeline: Received: February 11, 2024; Revised: March 24, 2024; Accepted: April 10, 2024; Published: May 15, 2024

Citation: Richter, M. G., & Meyer, D. W. (2024). Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Silicide Core-Shell Nanowire Interfaces. International Journal of Physics, 15(5), 33–40.

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