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MA: Fachverband Magnetismus

MA 25: Magnetic Heusler Compounds

MA 25.2: Vortrag

Mittwoch, 13. März 2013, 09:45–10:00, H10

Electronic structure of Fe2CrSi beyond the generalized gradient approximation — •Markus Meinert — Thin Films and Physics of Nanostructures, Department of Physics, Bielefeld University, 33615 Bielefeld, Germany

The ferromagnetic Heusler compound Fe₂CrSi has been predicted to be a half-metal from standard density functional theory calculations [1,2]. In the present study, we investigate the properties of Fe₂CrSi beyond the level of the generalized gradient approximation (GGA) within density functional theory. We compare the LDA, several GGAs, meta-GGAs including the Tran-Blaha modified Becke-Johnson potential (mBJLDA), hybrid functionals, the +U method, and one-shot GW. The TPSS and M06-L functionals, the mBJLDA model potential, GGA+U, and the hybrids predict Fe₂CrSi consistently as a semiconductor with a small majority and a larger minority gap. In most semilocal approximations we find a ferromagnetic groundstate, but M06-L, GGA+U, HSE06, and PBE0 predict Fe₂CrSi to be a ferrimagnet. The sensitivity of the groundstate of Fe₂CrSi makes this compound an ideal test case to assess the validity of the various available approximations for the density functional for the material class of 3d transition metal based Heusler compounds.

[1] Ishida et al., Mater. Trans. 47, 464 (2006). [2] Luo et al., J. Phys. D: Appl. Phys. 40, 7121 (2007).