Oscillation galvanomagnetic effect in double-layer metal films

Abstract

A semiclassical approximation has been used to analyze theoretically the dependence of the conductivity σ (resistivity ρ) of a double-layer film consisting of plane-parallel single-crystal metal layers of different thickness dj ≠ dn and grade lj ≠ ln on the layer thickness ratio d2,1 = d2/d1 and on the magnitude of the magnetic field normal to the layer interface. A general expression (for any d2,1) and asymptotic expressions (for thick and thin (compared to the electron free path lj) metal layers in a weak and a strong magnetic field) for the conductivity of a double-layer specimen have been obtained. A nonmonotonic relation between the conductivity of a double-layer film and the layer thickness ratio at weak magnetic fields has been predicted which is sensitive to the character of the interaction of charge carriers with the conductor boundaries. At strong magnetic fields, ρ becomes an oscillating function of magnetic field (layer thickness). A detailed numerical analysis of the resistivity of a double-layer film on the layer thickness ratio and on the magnetic field strength has been performed for arbitrary values of the parameters that describe the character of the interaction of charge carriers with the specimen boundaries.