Bulk and surface half-metallicity: The case of D03-type Mn 3Ge

Abstract

Motivated by the experimental realization of D022-type Mn 3Ge (001) films [Kurt et al. Appl. Phys. Lett. 101, 132410 (2012)] and the structural stability of D03-type Heusler alloy Mn 3Ge [Zhang et al. J. Phys.: Condens. Matter 25, 206006 (2013)], we use the first-principles calculations based on the full potential linearized augmented plane-wave method to investigate the electronic and magnetic properties of D03-type Heusler alloy Mn3Ge and its (001) surface. We show that bulk D03-Mn3Ge is a half-metallic ferromagnet with the minority-spin energy gap of 0.52 eV and the magnetic moment of 1.00 μB per formula unit. The bulk half-metallicity is preserved at the pure Mn-terminated (001) surface due to the large exchange split, but the MnGe-terminated (001) surface destroys the bulk half-metallicity. We also reveal that the surface stabilities are comparable between the D0 3-Mn3Ge (001) and the experimental D022-Mn 3Ge (001), which indicates the feasibility to grow the Mn 3Ge (001) films with D03 phase other than D022 one. The surface half-metallicity and stability make D03-Mn 3Ge a promising candidate for spintronic applications. © 2014 AIP Publishing LLC.