Structure, epitaxial growth and nucleation of CaO/SrO interfaces using energy minimisation, molecular dynamics and computer graphics

Abstract

Atomistic models of CaO/SrO interfaces have been constructedvia the sequential deposition of CaO species to SrO surfaces in conjunction with energy minimisation and dynamics. Using this approach the nucleation and growth mechanisms of CaO on the SrO support can be explored. The calculations suggest that the surface of the SrO substrate exacts a critical influence on the structure of the thin film. In particular, surface steps and roughness lead to incoherent films which are difficult to characterise with implications for the surface preparation of support materials. Conversely, the CaO species deposited may also degrade the SrO support: both charged and charge neutral surface vacancies on the SrO surface are created and surface steps are eroded during the deposition process. The results also suggest that the lattice misfit between the two materials is accommodated via defects and dislocations within the thin film in addition to considerable structural relaxation of the overlying thin film and the support.