Strain-Glass Dynamics in the Superionic Conductor Na3PS4
Abstract
Ionic conduction in solid-state electrolytes is conventionally described by mobile cations migrating through a static host lattice. Yet the fastest conductors are often the most disordered, and how disorder enhances transport remains unresolved at the mesoscale, inaccessible to ensemble-averaged probes. We use Bragg X-ray photon correlation spectroscopy to measure nanoscale structural dynamics of a single ball-milled Na3PS4 particle. We find that the cubic phase behaves as a strain glass: a frustrated configuration of three degenerate tetragonal variants with short-range order. Its domain-wall motion is stress-driven, crossing over irreversibly to thermally activated dynamics on annealing as residual milling stress is depleted. Rearrangements follow scale-free avalanche statistics, matching ferroelastic martensites but without external driving. The tetragonal polymorph shows none of these features and relaxes fifty times more slowly. These dynamics occur on timescales comparable to estimated ionic diffusion across the particle, indicating the host structure cannot be assumed static on transport-relevant timescales.
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BibTeX
@misc{lamb2026strainglass,
title = {{Strain-Glass Dynamics in the Superionic Conductor Na$_3$PS$_4$}},
author = {Erik S. Lamb and Nicolò D'Anna and Phillip Ridley and Nelson Hua and Ivan Zaluzhnyy and James Burrow and Emilio Escauriza and Robin Glefke and Boyan K. Stoychev and Mingze Wan and Zhe Ren and Fabian Westermeier and Michael Sprung and Alex Frañó and Ying Shirley Meng and Oleg G. Shpyrko},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.04547},
eprint = {2611.04547},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.04547},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Strain-Glass Dynamics in the Superionic Conductor Na_3PS_4
AU - Erik S. Lamb
AU - Nicolò D'Anna
AU - Phillip Ridley
AU - Nelson Hua
AU - Ivan Zaluzhnyy
AU - James Burrow
AU - Emilio Escauriza
AU - Robin Glefke
AU - Boyan K. Stoychev
AU - Mingze Wan
AU - Zhe Ren
AU - Fabian Westermeier
AU - Michael Sprung
AU - Alex Frañó
AU - Ying Shirley Meng
AU - Oleg G. Shpyrko
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.04547
UR - https://arxiv.org/abs/2611.04547
AB - Ionic conduction in solid-state electrolytes is conventionally described by mobile cations migrating through a static host lattice. Yet the fastest conductors are often the most disordered, and how disorder enhances transport remains unresolved at the mesoscale, inaccessible to ensemble-averaged probes. We use Bragg X-ray photon correlation spectroscopy to measure nanoscale structural dynamics of a single ball-milled Na_3PS_4 particle. We find that the cubic phase behaves as a strain glass: a frustrated configuration of three degenerate tetragonal variants with short-range order. Its domain-wall motion is stress-driven, crossing over irreversibly to thermally activated dynamics on annealing as residual milling stress is depleted. Rearrangements follow scale-free avalanche statistics, matching ferroelastic martensites but without external driving. The tetragonal polymorph shows none of these features and relaxes fifty times more slowly. These dynamics occur on timescales comparable to estimated ionic diffusion across the particle, indicating the host structure cannot be assumed static on transport-relevant timescales.
ER -