title: Electron correlations and the minority-spin band gap in half-metallic Heusler alloys.
abstract: Electron-electron correlations affect the band gap of half-metallic ferromagnets by introducing nonquasiparticle states just above the Fermi level. In contrast with the spin-orbit coupling, a large asymmetric nonquasiparticle spectral weight is present in the minority-spin channel, leading to a peculiar finite-temperature spin depolarization effects. Using recently developed first-principle dynamical mean-field theory, we investigate these effects for the half-metallic ferrimagnetic Heusler compound FeMnSb. We discuss depolarization effects in terms of strength of local Coulomb interaction U and temperature in FeMnSb. We propose Ni(1-x)Fe(x)MnSb alloys as a perspective materials to be used in spin-valve structures and for experimental search of nonquasiparticle states in half-metallic materials.
authors.affiliation: Institute of Theoretical Physics, Graz University of Technology, A-8010 Graz, Austria.
authors.forename: L
authors.initials: L
authors.lastname: Chioncel
authors.forename: E
authors.initials: E
authors.lastname: Arrigoni
authors.forename: M I
authors.initials: MI
authors.lastname: Katsnelson
authors.forename: A I
authors.initials: AI
authors.lastname: Lichtenstein