A Computational Study On the Mechanical Properties of Pentahexoctite Single-layer: Combining DFT and Classical Molecular Dynamics Simulations

TL;DR

This study combines DFT and classical molecular dynamics to investigate the elastic properties and fracture behavior of the newly proposed Pentahexoctite carbon monolayer, revealing its mechanical characteristics and fracture process.

Contribution

It provides the first detailed computational analysis of Pentahexoctite's mechanical properties using combined DFT and reactive MD simulations.

Findings

Young's modulus of 0.74 TPa for Pentahexoctite

Fracture occurs directly from elastic to fractured without plasticity

Elastic properties from DFT and MD are in good agreement

Abstract

Studies aimed at designing new allotropic forms of carbon have received much attention. Recently, a new 2D graphene-like allotrope named Pentahexoctite was theoretically proposed. Pentahexoctite has a metallic signature, and its structure consists of continuous 5-6-8 rings of carbon atoms with sp2 hybridization. Here, we carried out fully-atomistic computational simulations, combining reactive (ReaxFF) molecular dynamics (MD) and density functional theory (DFT) methods, to study the elastic properties and fracture patterns of Pentahexoctite monolayer. Results revealed a Young's Modulus of 0.74 TPa, smaller than the graphene one (about 1.0 TPa). The Pentahexoctite monolayer, when subjected to a critical strain, goes directly from elastic to completely fractured regimes. This process occurs with no plasticity stages between these two regimes. Importantly, graphene presents a similar fracture process. The elastic properties calculated with both DFT and MD are in good agreement. Keywords: Reactive Molecular Dynamics, DFT, Mechanical Properties, Carbon Allotrope,