New spin-polarization effect in photoemission from nonmagnetic surfaces

Abstract

Symmetry arguments and analytical calculation show that---contrary to common belief---photoelectrons emitted normal to (111) surfaces of nonmagnetic centrosymmetric cubic crystals by normally incident linearly polarized light may be spin polarized. Their spin is parallel to the surface and rotates by an angle 2\ensuremath{\alpha} upon rotation of the light polarization by \ensuremath{\alpha}. Numerical calculations using a relativistic multiple scattering formalism explicitly predict the effect for Pt(111), with a polarization up to 70%, and identify spin-orbit coupling in half-space intial states as its main cause.