Abstract
In probe-based microscopy, nanomanufacturing, and small-scale devices, the performance and reliability often depend on contacts between nanoscale bodies. Properties such as adhesion force, deformation of the near-surface material, and thermal or electrical transport across the contact can be load-dependent and difficult to predict and control. Traditional models of contact based on continuum mechanics rely on assumptions that are violated at the nanometer length scale. Here we used experiments and simulations to quantitatively investigate nanoscale asperities during formation, loading, and separation of contact. Experimentally, loading and unloading tests were performed inside of a transmission electron microscope. This enables the combination of high-resolution measurement of load and properties with simultaneous characterization of the material structure and geometry. Additionally, molecular dynamics simulations were performed on identical nanocontacts that are precisely matched in terms of materials, geometry, and loading conditions. The results demonstrate that the properties of nanocontacts cannot be fully described by traditional mechanics models, but instead require accounting for atomic-scale interactions.