A Critical Edge Number Revealed for Phase Stabilities of Two-Dimensional Ball-Stick Polygons

Fuente: arXiv
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Autores principales: Zhu, Ruijian, Wang, Yanting
Formato: Preprint
Publicado: 2023
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author Zhu, Ruijian
Wang, Yanting
author_facet Zhu, Ruijian
Wang, Yanting
contents Phase behaviors of two-dimensional (2D) systems constitute a fundamental topic in condensed matter and statistical physics. Although hard polygons and interactive point-like particles are well studied, the phase behaviors of more realistic molecular systems considering intermolecular interaction and molecular shape remain elusive. Here we investigate by molecular dynamics simulation thermal stabilities of 2D ball-stick polygons, serving as simplified models for molecular systems. Below the melting temperature $T_{m}$, we identify a critical edge number $n_{c}$, at which a waving superlattice structure emerges; when n < $n_{c}$,the triangular system stabilizes at a spin-ice-like glassy state; when n > $n_{c}$,the polygons stabilize at crystalline states, and $T_{m}$ is higher for polygons with more edges at higher pressures but exhibits a crossover for hexagon and octagon at low pressures. A theoretical framework taking into account the competition between entropy and enthalpy is proposed to provide a comprehensive understanding of our results, which is anticipated to facilitate the design of 2D materials.
format Preprint
id arxiv_https___arxiv_org_abs_2302_08305
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Critical Edge Number Revealed for Phase Stabilities of Two-Dimensional Ball-Stick Polygons
Zhu, Ruijian
Wang, Yanting
Soft Condensed Matter
Statistical Mechanics
Phase behaviors of two-dimensional (2D) systems constitute a fundamental topic in condensed matter and statistical physics. Although hard polygons and interactive point-like particles are well studied, the phase behaviors of more realistic molecular systems considering intermolecular interaction and molecular shape remain elusive. Here we investigate by molecular dynamics simulation thermal stabilities of 2D ball-stick polygons, serving as simplified models for molecular systems. Below the melting temperature $T_{m}$, we identify a critical edge number $n_{c}$, at which a waving superlattice structure emerges; when n < $n_{c}$,the triangular system stabilizes at a spin-ice-like glassy state; when n > $n_{c}$,the polygons stabilize at crystalline states, and $T_{m}$ is higher for polygons with more edges at higher pressures but exhibits a crossover for hexagon and octagon at low pressures. A theoretical framework taking into account the competition between entropy and enthalpy is proposed to provide a comprehensive understanding of our results, which is anticipated to facilitate the design of 2D materials.
title A Critical Edge Number Revealed for Phase Stabilities of Two-Dimensional Ball-Stick Polygons
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2302.08305