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

We demonstrated epitaxial growth of magnesium oxide (MgO) on a silicon (Si) substrate with cubic on cubic structure [MgO(001)//Si(001) and MgO(100)//Si(100)]. Epitaxial films were prepared using the 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 the 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 the crystal structure, (2) domain mismatch between MgO and Si instead of lattice mismatch, and (3) stability of MgO crystals on the surface of the Si substrate.