Interplay between Quantum Size Effect and Strain Effect on Growth of Nanoscale Metal Thin Film

TL;DR

This paper presents a theoretical framework analyzing how quantum size effects and strain influence the stability of metal nanofilms, revealing quantum oscillations in surface stress and emphasizing strain's role in experimental discrepancies.

Contribution

It introduces a coupled quantum and strain effect model for metal nanofilms, providing a way to estimate strain and explain experimental variations.

Findings

Large quantum oscillations in surface stress as a function of film thickness

Quantum oscillations are coupled with strain effects via quantum electronic stress

Strain significantly impacts the surface energy and stability of nanofilms

Abstract

We develop a theoretical framework to investigate the interplay between quantum size effect (QSE) and strain effect on the stability of metal nanofilms. The QSE and strain effect are shown to be coupled through the concept of "quantum electronic stress. First-principles calculations reveal large quantum oscillations in the surface stress of metal nanofilms as a function of film thickness. This adds extrinsically additional strain-coupled quantum oscillations to surface energy of strained metal nanofilms. Our theory enables a quantitative estimation of the amount of strain in experimental samples, and suggests strain be an important factor contributing to the discrepancies between the existing theories and experiments.