Spin Polarization of Photoelectrons from Si(001)

Abstract

Si 2p core photoelectron spectra are calculated for Si(001) for different elliptical polarization of the incident radiation and normal incidence. The degree of the elliptical polarization is varied continuously from right to left circularly polarized light including different cases of linear polarization [100], [110], [010] and [110]. Due to the surface the cubic C 4 screw axis and the (100) glide plane disappear. There remain a C 2 axis and the mirror planes (100) and (110). Thus we get different intensities for the polarizations [110] and [110], respectively. Due to the mirror planes (Φ 1 = 45°;135°) the relation P(θ, Φ 1 + Φ, ∈(α,ζ)) = -P(θ, Φ 1 - Φ, ∈ (2Φ 0 - α, -ζ)) connects the intensities of spin up and spin down electrons. The angles α and ζ describe the direction of the polarization. This relation is an essential view of the spin polarization. Results are presented in dependence on the azimuth angle Φ for fixed polar angle θ with respect to the surface normal direction.