Collective dynamics and shattering of disturbed two-dimensional Lennard-Jones crystals

TL;DR

This study combines numerical and analytical methods to explore how two-dimensional Lennard-Jones crystals respond to disturbances, revealing velocity field transitions, vacancy-driven shattering, and healing dynamics, thus advancing understanding of collective and disruptive behaviors in crystals.

Contribution

It introduces a comprehensive analysis of dynamical responses and crystal disruption mechanisms in 2D Lennard-Jones crystals under random disturbances, highlighting a novel vacancy-driven shattering process.

Findings

Identification of symmetric velocity fields with coherent and disordered regions

Discovery of an order-disorder transition in velocity fields

Observation of vacancy-driven crystal shattering under strong disturbances

Abstract

Elucidating collective dynamics in crystalline systems is a common scientific question in multiple fields. In this work, by combination of high-precision numerical approach and analytical normal mode analysis, we systematically investigate the dynamical response of two-dimensional Lennard-Jones crystal as a purely classical mechanical system under random disturbance of varying strength, and reveal rich microscopic dynamics. Specifically, we observe highly symmetric velocity field composed of sharply divided coherent and disordered regions, and identify the order-disorder dynamical transition of the velocity field. Under stronger disturbance, we reveal the vacancy-driven shattering of the crystal. This featured disruption mode is fundamentally different from the dislocation-unbinding scenario in two-dimensional melting. We also examine the healing dynamics associated with vacancies of varying size. The results in this work advance our understanding about the formation of collective dynamics and crystal disruption, and may have implications in elucidating relevant non-equilibrium behaviors in a host of crystalline systems.