Mechanical properties of nanosheets and nanotubes investigated using a new geometry independent volume definition

TL;DR

This paper introduces a new geometry-independent volume definition for nanosheets and nanotubes, enabling more accurate calculation of their mechanical properties like Young's modulus, especially at atomic scales.

Contribution

A novel volume definition based on electron density that improves the transferability of macroscopic concepts to nanoscale materials.

Findings

Calculated Young's moduli for graphene, BN, and MoS2 nanosheets and nanotubes.

Demonstrated Fermi level dependence of Young's modulus.

Explored out-of-plane Poisson's ratio implications.

Abstract

Cross-sectional area and volume become difficult to define as material dimensions approach the atomic scale. This limits the transferability of macroscopic concepts such as Young's modulus. We propose a new volume definition where the enclosed nanosheet or nanotube average electron density matches that of the parent layered bulk material. We calculate the Young's moduli for various nanosheets (including graphene, BN and MoS2) and nanotubes. Further implications of this new volume definition such as a Fermi level dependent Young's modulus and out-of-plane Poisson's ratio are shown.