Half-metallic, Magnetic, and Optical Properties for the (001) Surface of Binary Heusler Alloy MgCl3

Abstract

The half-metallic (HM), magnetic, and optical properties for the (001) surface of binary Heusler alloy MgCl3 were investigated by the first-principles method. The Mg*Mg*-term and Mg*Mg-term had the lower surface energies among the ClCl-term, Mg*Mg*-term, ClMg-term, ClCl*-term, and Mg*Mg-term (001) surfaces, thus, they were the more stable surfaces. The band decomposed charge density showed clearly the valence band maximum was contributed not only by the ClB-3p states but also the ClA-3p and ClC-3p states. The HM character was destroyed in all the five terminations of the (001) surface. The stable Mg*Mg*-term (001) surface had the largest spin polarization − 83.0%. The hydrogen-termination effect showed an effective method to enlarge the spin polarizations for the ClCl-term and ClCl*-term surfaces to produce thin films which had potential applications in spintronics. There were great changes of atomic magnetic moments for Cl atoms in any layer. In energy range of 1.6–3.1 eV for the visible light, the Mg*Mg*-term had superiority in the absorption for purple light.