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Gap state imaging and spin‐orbit effects in resonant photoelectron diffraction
Author(s) -
Krüger Peter,
Pieve Fabiana Da
Publication year - 2016
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6182
Subject(s) - atomic physics , diffraction , condensed matter physics , chemistry , spin polarization , scattering , x ray photoelectron spectroscopy , polarization (electrochemistry) , valence (chemistry) , physics , nuclear magnetic resonance , electron , optics , organic chemistry , quantum mechanics
In core‐level photoelectron diffraction, the surface atomic structure is imaged through a local source wave. In valence photoemission, the source wave gets effectively localized at a core‐valence resonance, and local information on valence states can be obtained. Through photoelectron diffraction at the Ti 2 p − 3 d resonance, we have determined the charge distribution of the gap state at n ‐doped TiO 2 surfaces. Second, the origin of spin polarization in resonant photoemission from non‐ferromagnetic surfaces is critically reviewed. We have developed a multiple scattering computational method for resonant photoemission and have applied it to Cr(110) and Fe(100). For circular polarized light, we find that the resonant photocurrent is strongly spin polarized in antiferromagnets and disordered ferromagnets, in agreement with experiment. Contrary to previous interpretations, we show that this spin polarization is essentially unrelated to local magnetic moments, but because of an angular momentum transfer from the photon to the photoelectron via core spin‐orbit coupling and exchange autoionization decay. Copyright © 2016 John Wiley & Sons, Ltd.