Half-metallicity of the (001), (111) and (110) surfaces of CoRuMnSi and interface half-metallicity of CoRuMnSi/CdS

Abstract

Recent studies have indicated that the quaternary Heusler alloy CoRuMnSi shows a half-metallic ferromagnetism (Kundu et al., Sci. Rep., 7, (2017), 1803). The (111), (110), and (001) surfaces and the interfaces with CdS (111) substrate of the quaternary Heusler alloy CoRuMnSi were explored by carrying out a first-principles investigation based on a density functional theory. Calculations showed that the half metallicity can be preserved for the Si-terminated (111) surface and subsurface while the half-metallicity approved in the bulk CoRuMnSi is destroyed at Co, Ru, and Mn-terminations (111) surfaces and subsurfaces. Regrettably, the surface states ruin the gap in the spin-down channel at both MnSi- and CoRu-terminated (001) surfaces and subsurfaces. Remarkably, the (110) surfaces and subsurfaces have a nearly half-metallicity property with a high spin polarization. Based on spin magnetic character calculations, the spin magnetic moments of surface and subsurface atoms are larger and smaller than those in the bulk quaternary Heusler alloy CoRuMnSi. For the interface of CoRuMnSi/CdS (111), the bulk half-metallicity is destroyed at Si–Cd and Si–S configurations.