Onset of Melting in Finite Ion Crystals: The Role of Structural Isomerization
Abstract
We theoretically investigate the microscopic mechanism of melting in finite two-dimensional ion crystals confined in anisotropic traps. Building on our previous studies of melting probability as a function of temperature and anisotropy, we extend the analysis to crystal sizes ranging from N=4 to N=101 ions and examine how structural isomerization modifies the melting pathways. Using molecular dynamics simulations together with Metropolis-Hastings equilibrium sampling, we analyze radial fluctuations, angular disorder, Lindemann parameters, and isomer-dependent energy landscapes in these Coulomb crystals. We find that crystals with identical particle number and trap anisotropy can exhibit substantially different melting behavior depending on the metastable structural isomer they occupy. Contrary to a simple soft-mode instability picture, the observed melting process is characterized by a gradual thermally-driven accumulation of radial and angular disorder. Structural isomerization reshapes the fluctuation channels through which delocalization develops, leading to nonuniform melting probabilities across temperature and anisotropy space. These results provide a unified microscopic picture of melting in finite ion crystals and clarify the role of structural rearrangements in finite-size phase transitions.
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BibTeX
@misc{pashinsky2026onset,
title = {{Onset of Melting in Finite Ion Crystals: The Role of Structural Isomerization}},
author = {Boris V. Pashinsky and Boris Blinov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.05624},
eprint = {2610.05624},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.05624},
}
RIS
TY - UNPB
TI - Onset of Melting in Finite Ion Crystals: The Role of Structural Isomerization
AU - Boris V. Pashinsky
AU - Boris Blinov
PY - 2026
DA - 2026/10/04
PB - arXiv
DO - 10.48550/arxiv.2610.05624
UR - https://arxiv.org/abs/2610.05624
AB - We theoretically investigate the microscopic mechanism of melting in finite two-dimensional ion crystals confined in anisotropic traps. Building on our previous studies of melting probability as a function of temperature and anisotropy, we extend the analysis to crystal sizes ranging from N=4 to N=101 ions and examine how structural isomerization modifies the melting pathways. Using molecular dynamics simulations together with Metropolis-Hastings equilibrium sampling, we analyze radial fluctuations, angular disorder, Lindemann parameters, and isomer-dependent energy landscapes in these Coulomb crystals. We find that crystals with identical particle number and trap anisotropy can exhibit substantially different melting behavior depending on the metastable structural isomer they occupy. Contrary to a simple soft-mode instability picture, the observed melting process is characterized by a gradual thermally-driven accumulation of radial and angular disorder. Structural isomerization reshapes the fluctuation channels through which delocalization develops, leading to nonuniform melting probabilities across temperature and anisotropy space. These results provide a unified microscopic picture of melting in finite ion crystals and clarify the role of structural rearrangements in finite-size phase transitions.
ER -