Strain sensing through the resonant properties of deformed metal nanowires

Abstract

In this article, we study the potential of gold nanowires as resonant nanoscale strain sensors. The sensing ability of the nanowires is determined by calculating the variations in resonant frequency that occur due to applied uniaxial tensile and compressive strain. The resonant frequencies are obtained using the surface Cauchy–Born model, which captures surface stress effects on the nanowires through a nonlinear continuum mechanics framework; due to the continuum formulation, the strain-dependent nanowire resonant frequencies are calculated through the solution of a standard finite element eigenvalue problem, where the coupled effects of the applied uniaxial strain and surface stress are naturally included through the finite element stiffness matrix. The nanowires are found to be more sensitive to compressive than tensile strain, with resonant frequency shifts around 200–400 MHz with the application of 1% tensile and compressive strain. In general, the strain sensitivity of the nanowires is found to increase with decreasing cross-sectional size, with additional dependencies on their aspect ratio.