Stress driven fractionalization of vacancies in regular packings of elastic particles

TL;DR

This paper investigates how stress causes vacancies in 2D elastic particle packings to fractionalize into dislocation pairs, revealing new defect interactions and implications for material design.

Contribution

It demonstrates a universal vacancy fractionalization process driven by local shear stress in 2D crystal models, linking defect behavior with mechanical stress.

Findings

Vacancies under compression split into dislocation pairs.

The fractionalization process is triggered by local shear stress.

Vacancy fractionalization influences defect interactions and material properties.

Abstract

Elucidating the interplay of defect and stress at the microscopic level is a fundamental physical problem that has strong connection with materials science. Here, based on the two-dimensional crystal model, we show that the instability mode of vacancies with varying size and morphology conforms to a common scenario. A vacancy under compression is fissioned into a pair of dislocations that glide and vanish at the boundary. This neat process is triggered by the local shear stress around the vacancy. The remarkable fractionalization of vacancies creates rich modes of interaction between vacancies and other topological defects, and provides a new dimension for mechanical engineering of defects in extensive crystalline structures.