Non-quasiparticle states in the core level spectra of ferromagnetic semiconductors and half-metallic ferromagnets

The Green’s functions that determine X-ray spectra are calculated in the s-d exchange model of a saturated conducting ferromagnet in the presence of the core hole. It is demonstrated that the core level (X-ray absorption, emission and photoelectron) spectroscopy might be an efficient tool to investigate the nonquasiparticle (NQP, spin-polaron) states in electron energy spectrum since the core hole potential can enhance essentially their spectral weight. NQP contributions to resonant X-ray scattering spectra can be also much more pronounced than those to the the density of states. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2005