Effect of three dimensional interface in determination of spin polarization using Andreev reflection spectroscopy

A theoretical study of a three-dimensional (3D) normal metal/superconductor interface with arbitrary spin polarization and interface geometry is presented. The interface geometry can drastically affect the Andreev spectrum due to the 3D injection. The 3D effect can be attributed to a larger interfacial scattering factor in the 1D model, yielding the same intrinsic spin polarization and superconducting gap as the 3D model. This demonstrates that the 1D model can be utilized to extract the intrinsic spin polarization and the superconducting gap values for a 3D interface as long as the interfacial scattering factor is not concerned.