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Home > Issues > Volume 12 (2007) > No.3(pp.93-132)
Surface Electronic Structures and Magnetism of a Full-Heusler Alloy Co2CrGa(001) : A First-principles Study
Journal of Magnetics, Volume 12, Number 3, 30 Sep 2007, Pages 97-102
Ying-Jiu Jin(Department of Physics, Inha University), Jae-Il Lee* (Department of Physics, Inha University)
We have investigated the electronic structures and magnetism of a full Heusler alloy Co2CrGa(001) surface by using the all-electron full-potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation (GGA). We considered two types of different terminations: the Co-terminated (Co-Term) and the CrGa-terminated (CrGa-Term) surfaces. From the calculated layer-projected density of states (LDOS), we found that the surface of the CrGa-Term shows nearly half-metallic character while that of the Co-Term is far from the half-metallic. For the Co-Term, the surface Co atom moves down to the bulk region by 0.05ÅA , while the subsurface Cr and Ga atoms move up to the surface layer by 0.05 and 0.01Å, respectively. For the CrGa-Term, there is a large inward relaxation of the surface Ga atom(0.07Å) ,but the relaxation of the surface Cr atom is very small(0.01Å).The relaxations affect not much to the overall shapes of DOS for both terminations, but make the surface states of the surface Cr and Ga atoms for the CrGa-Term shift to higher energy that enhances the nearly half-metallic character of the CrGa-Term. The magnetic moments of the surface Cr(2.28µB) in the CrGa-Term and the surface Co(1.17µB)in the Co-Term were much increased compared to those of the inner-layers(1.79 and 0.77µB), respectively, while that of the subsurface Cr atom in the Co-Term was decreased to 1.19µB.
Keywords: half-metallicity; electronic structure; magnetism; Co_2CrGa
DOI: 10.4283/JMAG.2007.12.3.97
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