# Discontinuous evolution of the structure of stretching polycrystalline graphene

## TL;DR

This paper reveals that polycrystalline graphene exhibits abrupt, avalanche-like out-of-plane displacements and hysteresis under stretching, affecting its mechanical and thermal properties, as shown through computer simulations.

## Contribution

It demonstrates the discontinuous, hysteretic response of polycrystalline graphene's structure to stretching, highlighting a new aspect of its dynamical elasticity.

## Key findings

- Discontinuous displacements observed in simulations
- Hysteretic behavior during stress cycling
- Implications for mechanical and thermal properties

## Abstract

Polycrystalline graphene has an inherent tendency to buckle, i.e. develop out-of-plane, three-dimensional structure. A force applied to stretch a piece of polycrystalline graphene influences the out-of-plane structure. Even if the graphene is well-relaxed, this happens in non-linear fashion: occasionally, a tiny increase in stretching force induces a significant displacement, in close analogy to avalanches, which in turn can create vibrations in the surrounding medium. We establish this effect in computer simulations: by continuously changing the strain, we follow the displacements of the carbon atoms that turn out to exhibit a discontinuous evolution. Furthermore, the displacements exhibit a hysteretic behavior upon the change from low to high stress and back. These behaviors open up a new direction in studying dynamical elasticity of polycrystalline quasi-two-dimensional systems, and in particular the implications on their mechanical and thermal properties.