title: Half-metallic interface between a Heusler alloy and Si.
abstract: The interface between the half-Heusler alloy CoFeSi and Si is investigated by using first-principles density-functional calculations. Although CoFeSi has not been fabricated yet, its formation energy turns out to be negative. Within the generalized gradient approximation, CoFeSi shows nearly half-metallic properties, and its lattice constant is about 5.38 Å; this value is relatively close to the lattice constant of Si. We here chiefly investigate the CoFeSi/Si (110) interface, and find that the half-metallic properties are almost preserved at a specific (110) interface. Furthermore, the interfacial structure which leads to the high spin polarization has the lowest energy of the (110) interfacial patterns examined in this work. The half-metallicity at the interfaces is similarly observed in the densities of states projected onto delocalized sp states, and this suggests the relevance of the high spin polarization to transport properties.
authors.affiliation: Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Abe
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Miura
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Shiozawa
authors.forename: Masafumi
authors.initials: M
authors.lastname: Shirai