Effects of surface stress on the elastic moduli of thin films and superlattices

R. C. Cammarata, K. Sieradzki

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Abstract

A thermodynamic model which predicts a significant sample-size effect on the elastic properties of very thin films and small-period superlattices is presented. Compressive surface stresses cause the in-plane interatomic distances in a thin metal film to decrease as the thickness decreases. For copper films with a thickness of 0.75 nm, a 1% in-plane biaxial compressive strain is obtained which gives rise to a 50% increase in the biaxial modulus. This model also predicts a similar modulus enhancement (supermodulus effect) in multilayered thin films due to strains caused by incoherent interfacial stress.

Original languageEnglish (US)
Pages (from-to)2005-2008
Number of pages4
JournalPhysical Review Letters
Volume62
Issue number17
DOIs
StatePublished - Jan 1 1989

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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