Mechanical Properties and Fracture Phenomenon of Defected Monolayer Indium Selenide: A Molecular Dynamics Study

TL;DR

This study uses molecular dynamics simulations to analyze the mechanical properties and fracture mechanisms of defected monolayer InSe nanosheets, revealing brittle failure behavior and directional differences in fracture resistance.

Contribution

It provides new insights into the fracture behavior of defected InSe monolayers, including the limitations of Griffith's criterion at the nanoscale.

Findings

Brittle fracture governs failure in defected InSe nanosheets.

Armchair bonds resist crack propagation more than zigzag bonds.

Griffith's criterion has limited applicability for nano-cracks in InSe.

Abstract

In this study, we report the mechanical properties and fracture mechanism of pre-cracked and defected InSe nanosheet samples using molecular dynamics (MD) simulations. We noticed that the failure of pre-cracked and defected InSe nanosheet is governed by brittle type fracture. Armchair directional bonds exhibit a greater resistance for crack propagation relative to the zigzag directional ones. Thus, fracture strength of the pre-cracked sheet is slightly higher for zigzag directional loading than that for armchair. We evaluated the limitation of the applicability of Griffith's criterion for single layer (SL) InSe sheet for nano-cracks as the brittle failure of Griffith prediction demonstrates significant differences with the MD fracture strength. We inspected the effect of temperature on the mechanical properties of the pre-cracked samples of SLInSe. We also discussed the fracture mechanism of both defected and pre-cracked structure at length.