Atomistic Origin and Strain Control of the Finite-Temperature Dielectric Response in BaTiO3

Ryotaro Sahashi; Po-Yen Chen; Teruyasu Mizoguchi

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arXiv · 2609.07219

Atomistic Origin and Strain Control of the Finite-Temperature Dielectric Response in BaTiO3

Ryotaro Sahashi·Po-Yen Chen·Teruyasu Mizoguchi

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Abstract

Soft-mode theory specifies a frequency, not what a local polar unit does. What real-space motion underlies the dielectric response of BaTiO3 therefore remains unclear. Using electric-field-induced molecular dynamics with a machine-learning force field, we show that the permittivity tracks the field-induced angular redistribution of local Ti-O off-centering, not its magnitude. Temperature and biaxial strain modify the local structure through different microscopic routes, yet both dielectric responses collapse onto a common relation with the same orientational descriptor, providing a real-space counterpart to soft-mode behavior.

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Ryotaro Sahashi, Po-Yen Chen, Teruyasu Mizoguchi. 2026-09-18. Atomistic Origin and Strain Control of the Finite-Temperature Dielectric Response in BaTiO3. https://arxiv.org/abs/2609.07219

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