Quantum Manifestation of Elastic Constants in Nanostructures

TL;DR

This paper demonstrates how quantum size effects significantly influence the elastic constants of nanostructures, especially in metallic systems, using first-principles calculations on Pb nanofilms and graphene nanoribbons.

Contribution

It reveals the dominance of quantum size effects over surface effects in determining elastic properties of nanostructures, providing new insights into quantum nanomechanics.

Findings

QSE significantly affects elastic constants in metallic nanostructures

SS effects are more prominent in semiconductor and insulator nanostructures

First-principles calculations confirm the quantum influence on nanomechanical properties

Abstract

Generally, there are two distinct effects in modifying the properties of low-dimensional nanostructures: surface effect (SS) due to increased surface-volume ratio and quantum size effect (QSE) due to quantum confinement in reduced dimension. The SS has been widely shown to affect the elastic constants and mechanical properties of nanostructures. Here, using Pb nanofilm and graphene nanoribbon as model systems, we demonstrate the QSE on the elastic constants of nanostructures by first-principles calculations. We show that generally QSE is dominant in affecting the elastic constants of metallic nanostructures while SS is more pronounced in semiconductor and insulator nanostructures. Our findings have broad implications in quantum aspects of nanomechanics.