Angular Dependence of Four Mechanical Properties of Graphynes

TL;DR

This study investigates how four key mechanical properties of various graphyne structures depend on direction, revealing significant variability and specific null compressibility directions in asymmetric forms.

Contribution

It provides new insights into the angular dependence of elastic properties in asymmetric graphynes, expanding understanding beyond symmetric structures.

Findings

Young's modulus varies by a factor of 10 depending on direction.

Directions of null linear compressibility identified in some asymmetric structures.

Elastic properties depend strongly on the orientation in graphyne materials.

Abstract

Graphyne is a porous two-dimensional carbon allotrope of graphene that possesses interesting physical properties, including non-null bandgap. It is composed of carbon hexagonal rings or carbon-carbon bonds connected by acetylenic chains. The diverse forms of these connections yield a variety of graphyne structures. In a previous study, we have obtained the elastic properties of seven distinct families of graphyne structures as a function of the number of acetylene chains, from 1 to 10. The Young's modulus, shear modulus, Poisson's ratio and linear compressibility were predicted for the zigzag and armchair directions of all 70 graphyne structures. Here, we present some noteworthy findings regarding the angular dependence of these four elastic properties of asymmetric graphynes. Our results demonstrate that in a single structure, the minimum and maximum Young's modulus can vary by a factor of 10. Additionally, the directions of null linear compressibility in some asymmetric structures were determined.