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Half‐metallicity and magnetism at Heusler alloy surfaces: Co 2 MSi(001) (M = Ti, Cr)
Author(s) -
Jin Ying Jiu,
Lee Jae Il
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200723628
Subject(s) - magnetism , magnetic moment , metallicity , fermi level , condensed matter physics , atom (system on chip) , materials science , alloy , electron , physics , galaxy , metallurgy , quantum mechanics , computer science , embedded system
We investigated the electronic structures, magnetism, and half‐metallicity at the (001) surfaces of full‐Heusler alloys, Co 2 MSi (M = Ti, Cr), by using the all‐electron full‐potential linearized augmented plane wave method within the generalized gradient approximation. Both the Co‐terminated (Co‐term) and the MSi‐terminated (MSi‐term) surfaces were considered. From the calculated atom‐resolved density of states, we found that the half‐metallicity was destroyed at the Co‐term surfaces for both alloys. The electronic structures at the MSi‐term surfaces of the two alloys showed much different behavior. The half‐metallicity was retained at the TiSi‐term for Co 2 TiSi(001) but the minority spin gap was much reduced due to surface states located just below the Fermi level. On the other hand the half‐metallicity was destroyed at the CrSi‐term of Co 2 CrSi(001) due to the surface states located at the Fermi level. The calculated magnetic moment of the surface Co atom of the Co‐term for Co 2 CrSi(001) was increased slightly to 1.05 μ B with respect to that of the deep inner layers (∼1.00 μ B ), while that for Co 2 TiSi(001) was decreased to 0.88 μ B . Large enhancement of the magnetic moment was found for the surface Ti atoms at TiSi‐term of Co 2 TiSi(001) and Cr atoms at CrSi‐term of Co 2 CrSi(001) with values of 0.07 μ B and 2.91 ( B , respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)