Dichroic Photoemission for Pedestrians
Until very recently it was commonly believed that core level photoemission would not depend on the linear or circular polarization of the incident photon, except in the near threshold region. However, in localized materials such as transition metal, rare earth, and actinide compounds there is a strong interaction between the core hole and the valence electrons which can result in spin and orbital polarization of the core level and consequently in dichroic photoemission.1 This phenomenon differs from magnetic x-ray dichroism (MXD),2 where the core electron is excited into the unoccupied part of the 3d level. The dichroism is then primarily caused by the Pauli exclusion principle, i.e. only electrons with specific spin and orbital magnetic quantum numbers can be excited into the empty valence states. In x-ray photoemission the electron is excited into continuum states which have no magnetic structure far above the Fermi level and the dichroism is induced by core-valence interaction.
KeywordsCircular Dichroism Core Level Magnetic Circular Dichroism Linear Dichroism Core Hole
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- 17.G. van der Laan, Int. J. Mod. Phys. B 8, in print (1994).Google Scholar