Stiffness Constants and Strain Energy Densities of fcc and bcc Cubic Overlayers

The difference between the bulk spacings of a crystal and the spacings at and near the surface constitutes “surface misfit” and accordingly implies stressed surface layers. Stresses are determined by stiffness constants (STF.CON.). The STF.CON. are specified in principal (cube) axes and must be transformed to the local coordinate system which is chosen for stress and strain analysis of overlayers. The transformation matrices appropriate to fcc {100}, {110}, {111}, {133}, {113}, bcc {110} and {122} overlayers, STF.CON. and Hookian relations for the ultra-thin overlayers have been derived. Also the strain energy densities for the overlayers are discussed.