Extreme Anharmonicity and Thermal Contraction of One-Dimensional Wires.

Cignarella, Chiara; Bastonero, Lorenzo; Monacelli, Lorenzo; Marzari, Nicola · Nano Lett · 2025

basic_science · Level V

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Abstract

Ultrathin nanowires could play a central role in next-generation downscaled electronics. Here, we explore some of the most promising candidates identified from previous high-throughput screening─CuC<sub>2</sub>, TaSe<sub>3</sub>, and AuSe<sub>2</sub>─to gain insight into the thermodynamic and anharmonic behaviors of nanowires that could be exfoliated from weakly bonded three-dimensional materials. We analyze thermal stability, linear thermal expansion, and anharmonic heat capacity using the stochastic self-consistent harmonic approximation. Notably, our work unveils exotic features common among all one-dimensional wires: a colossal record negative thermal expansion and very large deviations from the Dulong-Petit law due to strong anharmonicity.