Application of photoelectron diffraction theory to circular dichroism and spin-polarized photoelectron emission

摘要

We have developed theoretical methods for calculating the circular dichroism (CD), spin polarization (SP), magnetic circular dichroism (MCD), and magnetic linear dichroism (MLD) in core-level photoemission with circularly-polarized and linearly-polarized light. The formalism generalizes our previous computer codes for a fully-converged multiple-scattering treatment of photoelectron diffraction. The results of these new calculations are compared to experimental data from various groups for several illustrative cases: CD in photoemission from "non-chiral" surfaces [CO on Pd(111), and Si(001)]; SP photoemission from nonmagnetic and magnetic atoms and surfaces [Xe, W(110), and Fe(110)], and MCD from Fe(110). We discuss the conditions that give rise to circular dichroism in the absence of structural chirality or magnetism. We also emphasize the strong interplay between non-magnetic CD and magnetic CD, as well as the highly anisotropic behavior of SP emission and its importance in SP photoelectron diffraction studies of magnetic order.