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arXiv · 2610.10165

Lattice dynamics of disordered phases of silicon and spatially resolved computations of thermal conductivity

A. Gautam·C. Ugwumadu·L. A. M. Rosset·R. M. Tutchton·S. Nakhmanson·D. A. Drabold
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Abstract

The lattice dynamics of disordered systems (amorphous solids, polymers and glasses) are often distinct from crystalline analogues. Examples include the "two-level systems" and the Boson peak. Here, we show that even the venerable material amorphous silicon offers new wrinkles: (1) realistic networks studied with DFT-quality interatomic potentials show the existence of harmonic modes exhibiting anomalously large root-mean-square variation in atomic positions, and (2) these dynamics determine the processes of heat transport. We correlate the atomic dynamics with transport using the site-projected thermal conductivity [C. Ugwumadu et. al Phys. Status Solidi B 263, e202500316 (2026)], and conjecture that these observations are relevant to other disordered systems.

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A. Gautam, C. Ugwumadu, L. A. M. Rosset, R. M. Tutchton, S. Nakhmanson, D. A. Drabold. 2026-10-07. Lattice dynamics of disordered phases of silicon and spatially resolved computations of thermal conductivity. https://arxiv.org/abs/2610.10165

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