Probing Anharmonic and Heterogeneous Carrier Dynamics Across Sublattice Melting in a Minimal Model Superionic Conductor

Fuente: arXiv
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Autori principali: Niyogi, Sucharita, Nakamura, Takenobu, Kobayashi, Genki, Ando, Yasunobu, Kawasaki, Takeshi
Natura: Preprint
Pubblicazione: 2026
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author Niyogi, Sucharita
Nakamura, Takenobu
Kobayashi, Genki
Ando, Yasunobu
Kawasaki, Takeshi
author_facet Niyogi, Sucharita
Nakamura, Takenobu
Kobayashi, Genki
Ando, Yasunobu
Kawasaki, Takeshi
contents Despite decades of research, the microscopic origin of sublattice melting and fast ion transport in superionic conductors remains elusive. Here, we introduce a chemically neutral minimal binary model consisting of a rigid host lattice stabilized by short-range steric repulsion and a soft carrier sublattice interacting via long-range Wigner-type forces. This contrast naturally produces distinct melting temperatures and an intermediate sublattice-melting phase in which carriers become fluidlike while the host remains crystalline. Molecular-dynamics simulations identify three dynamical regimes-crystalline, sublattice-melt, and fully molten-marked by sharp changes in diffusivity, structural correlations, and dynamic heterogeneity. Near sublattice melting, carrier motion is strongly anharmonic and spatially heterogeneous, beyond mean-field hopping descriptions. By tuning the density, we demonstrate that sublattice melting can be continuously controlled, establishing a direct link between lattice softness, anharmonicity, and collective ion transport. This work provides a unified microscopic foundation for designing mechanically robust, high-performance superionic conductors operable near ambient conditions.
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id arxiv_https___arxiv_org_abs_2602_05545
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Probing Anharmonic and Heterogeneous Carrier Dynamics Across Sublattice Melting in a Minimal Model Superionic Conductor
Niyogi, Sucharita
Nakamura, Takenobu
Kobayashi, Genki
Ando, Yasunobu
Kawasaki, Takeshi
Soft Condensed Matter
Disordered Systems and Neural Networks
Materials Science
Despite decades of research, the microscopic origin of sublattice melting and fast ion transport in superionic conductors remains elusive. Here, we introduce a chemically neutral minimal binary model consisting of a rigid host lattice stabilized by short-range steric repulsion and a soft carrier sublattice interacting via long-range Wigner-type forces. This contrast naturally produces distinct melting temperatures and an intermediate sublattice-melting phase in which carriers become fluidlike while the host remains crystalline. Molecular-dynamics simulations identify three dynamical regimes-crystalline, sublattice-melt, and fully molten-marked by sharp changes in diffusivity, structural correlations, and dynamic heterogeneity. Near sublattice melting, carrier motion is strongly anharmonic and spatially heterogeneous, beyond mean-field hopping descriptions. By tuning the density, we demonstrate that sublattice melting can be continuously controlled, establishing a direct link between lattice softness, anharmonicity, and collective ion transport. This work provides a unified microscopic foundation for designing mechanically robust, high-performance superionic conductors operable near ambient conditions.
title Probing Anharmonic and Heterogeneous Carrier Dynamics Across Sublattice Melting in a Minimal Model Superionic Conductor
topic Soft Condensed Matter
Disordered Systems and Neural Networks
Materials Science
url https://arxiv.org/abs/2602.05545