Constriction of lattice constant in epitaxial magnesium oxide film deposited on silicon substrate

We demonstrated epitaxial growth of magnesium oxide (MgO) on silicon (Si) substrate with cubic on cubic structure [MgO(001) // Si(001) and MgO(100) // Si(100)]. Epitaxial films were prepared by using pulsed laser deposition method, and with dependent on deposition conditions of oxygen partial pressure and substrate temperature, the lattice constants of MgO decreased along both surface normal and in-plane directions. To support the facts of (1) constriction of lattice constants and (2) cubic on cubic growth, we show (1) optimal lattice constants with defects in crystal structure, (2) domain mismatch between MgO and Si instead of lattice mismatch, and (3) stability of MgO crystal on the surface of Si substrate.