ELECTRICAL RESISTIVITY OF VERY THIN METALLIC FILMS WITH ISOTROPIC AND ANISOTROPIC SURFACES

摘要

A quantum mechanical approach is developed to calculate the surface-induced electrical conductivities of very thin metallic films with isotropic and anisotropic surfaces. Two particular cases are analyzed with this formalism: (1) films with isotropic surfaces and (2) films with anisotropic surfaces which have different morphological properties along two orthogonal directions. It is shown that, depending on the differences between these morphological properties, the surface-induced resistivities can be different along these directions. In order to investigate the validity of these predictions we have fabricated Pt films, with thickness in the 0.90 ≤ d ≤ 11.10 nm range, with very different morphological properties along two orthogonal directions. Measuring the electrical resistivities of these films, we have found different resistivities along these directions. We show that this anisotropic resistivity can be well explained by our theoretical approach.