Half-metallic properties of the (1 1 0) surface of alkali earth metal monosilicides in the zinc blende phase

Abstract

An all electron ab initio method was employed to study the electronic and magnetic properties of the (1 1 0) surface of alkaline-earth metal silicides: CaSi, SrSi and BaSi, in the zinc blende structure. The three surfaces are found to conserve the half-metallic properties of their bulk structures with a wide semiconducting energy gap in the spin-up channel. Half-metallic energy gap at the surfaces is small. In the CaSi surface it is of the order of k B T , which indicates that in the CaSi (1 1 0) a transition to a metallic state is possible due to temperature fluctuations. At the same time, the CaSi surface exhibits the strongest magnetic properties with 0.91 μ B magnetic moment on the Si atom in the topmost layer and 0.21 μ B magnetic moment on the Ca atom. In each of the three surfaces we observe a reduction of magnetic moments on the atoms in the subsurface layer and the enhancement of the magnetic moment on the atoms in the topmost layer, as compared with the properties of atoms in the bulk. An analysis of the calculated total and atom projected densities of states leads to a conclusion that the surface effects in the structures are short-range phenomena.

Fully spin-polarized quadratic non-Dirac bands realized quantum anomalous Hall effect

“…It is consistent with its bulk structure. [22][23][24][25] In addition, we calculated the magnetocrystalline anisotropy energies (MAE) of the BaX unit cell by considering the SOC effect. Here, we consider two magnetization directions, namely, the in plane ([100] direction) and out of plane ([001] direction).…”

“…Simultaneously, the alkali earth metal BaX (X = Si, Ge, Sn) system find unique ferromagnetic (FM) half-metal. [22][23][24][25] Interestingly, these compounds do not include any transition metal atoms. Hence, the mechanism of the ferromagnetism is different from the p-d exchange and double exchange that are crucial in the magnetic materials.…”

First-principles study on the half-metallicity of full-Heusler alloy Co2VGa (111) surface

“…It indicates that the Ga-terminated surface is stable, and this surface does not cause a strong relaxation due to the presence of broken bonds at the surface. 36 The Co-Ga-terminated surface is unstable.…”