Application of the phase field crystal model to strained metallic overlayers

Most metallic systems experience a phenomenon called surface reconstruction where the surface atoms on a crystal have a structure that is different from the bulk. Surface reconstruction often arises in heteroepitaxial systems, where a crystalline adsorbate film is grown on a crystalline substrate of a different material. In such systems, a mismatch is present between the lattice spacing of the adsorbate and that of the substrate. Due to the mismatch, strain is generated at the interface between the materials, which often leads to spontaneous surface patterning. In this thesis, an amplitude expansion methodology of the Phase-field crystal (PFC) model is used to model the structure of stable and metastable heteroepitaxial films on length scales of several hundred nanometres while being also able to resolve the atomistic resolution. We were able to reproduce realistically the surface ordering that can be seen experimentally in many metallic heteroepitaxial overlayers and make predictions for systems where the experimental results are limited.