Relativistic theory of photoemission and bremsstrahlung from ferromagnets

Abstract

On the basis of an effective Dirac-Hamiltonian, which describes the interaction of a quasiparticle or quasihole with a semi-infinite crystalline ferromagnet well below the Curie temperature, a one-step-model Green function theory of energy-, angle- and spin-resolved ultraviolet photoemission and bremsstrahlung is formulated. The elastic photocurrent spin density matrix is evaluated in a manner analogous to a Schrodinger-equation-based layer-KKR method (due to Pendry). Since the authors spin-dependent formalism includes both spin-orbit coupling and magnetic exchange, its applicability extends from ferromagnets a fortiori to non-magnetic materials, in particular those with strong spin-orbital coupling.