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

International Journal of Physics | Vol. 17, No. 4, April 2026 | pp. 25–32

DOI: 10.46882/2026/IJP/000192

Research Article

Title: Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Germanide 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-germanide (Si-Mg2Ge) 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; germanide interfaces

Manuscript Timeline: Received: January 08, 2026; Revised: February 17, 2026; Accepted: March 09, 2026; Published: April 10, 2026

Citation: Richter, M. G., & Meyer, D. W. (2026). Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Germanide Core-Shell Nanowire Interfaces. International Journal of Physics, 17(4), 25–32.

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