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Electron Correlations and the Minority-Spin Band Gap in Half-Metallic Heusler Alloys

L. Chioncel·E. Arrigoni·M. I. Katsnelson·A. I. Lichtenstein
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Abstract

Electron-electron correlations affect the band gap of half-metallic ferromagnets by introducing non-quasiparticle states just above the Fermi level. In contrast to the spin-orbit coupling, a large asymmetric non-quasiparticle 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 non-quasiparticle states in half-metallic materials.

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L. Chioncel, E. Arrigoni, M. I. Katsnelson, A. I. Lichtenstein. 2006-01-17. Electron Correlations and the Minority-Spin Band Gap in Half-Metallic Heusler Alloys. https://doi.org/10.1103/physrevlett.96.137203

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