Dispersion forces and hamaker constants for intergranular films in silicon nitride from spatially resolved-valence electron energy loss spectrum imaging

摘要

The van der Waals(vdW) dispersion forces represent one of the fundamental long range inter- facial and surface forces in materials. The dispersion forces, for a set of materials in close proximity, arise from the electronic structure of the materials wherein the electrons in interatomic bonds acting as oscillat- ing dipoles exhibit and attractive interaction energy. These vdW dispersion forces, represented by a propor- tionality constant, the full spectral Hamaker constant(A), can be calculatied directly from optical property based electronic structure spectra such as the interband transition strength(Jcv) using the Lifshitz theory.