Epitaxy-induced stresses as an efficient materials-design tool

It is well known that epitaxial stress/strain conditions in thin films may result in stabilization of rather exotic and highly-distorted phases that would otherwise not exist in strain-free bulk materials. Biaxial planar stresses acting in plane parallel to heterogeneous layers can alter quite uniquely thermodynamic properties, structural parameters, elastic properties as well as magnetic and electronic states of thin films. It was also shown that there is a strong connection between the behavior of overlayers and bulk material at high shape deformations. Here we describe the epitaxy-induced changes generated by small and moderate stresses and introduce suitable quantum-mechanical and atomistic approaches to these strained states. Focusing on elemental metals, transition-metal nitrides and half-metallic transition-metal oxides, selected structural, electronic and magnetic phase transformations are discussed and their impact on film properties is shown.