Half-metallicity of (0Â 0Â 1), (1Â 1Â 0) and (1Â 1Â 1) surfaces of zinc-blende MnBi and their interfaces with HgTe: A first-principle investigation

A first-principle study of structural, electronic and magnetic properties of the bulk on (1 1 1), (1 1 0), and (0 0 1) surfaces of zinc-blende manganese bismuth and the MnBi/HgTe (0 0 1) and (1 1 0) interfaces is undertaken. In case of the bulk, the compound exhibits half-metallicity with an energy gap of 1.27 eV in the minority-spin direction at the equilibrium lattice constant of 6.412 Ǻ. The results show that the half-metallicity of this bulk is well preserved on the surfaces considered here except for the Bi-terminated (0 0 1) and Mn-terminated (1 1 1) surfaces. Moreover, we find that the spin magnetic moments at the (1 1 1), (0 0 1) and (1 1 0) surfaces increase compared to those of the bulk MnBi, while they decrease on the (1 1 1), (0 0 1) and (1 1 0) subsurfaces. As we calculate the adhesion energy, it is found to be the most stable interface. We find out as will that the Bi-Te(0 0 1) configuration is the most stable between the two possible configurations of the MnBi/HgTe (0 0 1) interface. Regrettably, interfacial configurations show that the half-metallicity of bulk MnBi is ruined for all possible configurations.