Preserving stable 100% spin polarization at (111) heterostructures of half-metallic Heusler alloy Co_2VGa with semiconductor PbS

摘要

Based on the ha1f-metallicity confirmed experimentally in bulk Heusler alloy Co_2VGa, we use the first-principles calculations to extend our previous studies on the Co_2VGa (111) surfacial properties to the interfaces of Co_2VGa/PbS (111) heterostructures in which four possible interfacial structures are considered between the V- and Ga-terminated (111) surfaces of Co_2VGa and S- and Pb-terminated (111) surfaces of PbS. From the atomic density of states, it is shown that the half-metallicity of the bulk system is destroyed at Ga-S and Ga-Pb configurations while V-S and V-Pb configurations exhibit 100% spin polarization and nearly 100% spin polarization, respectively. Furthermore, the structure relaxation and the calculated interfacial adhesion energies indicate that V-S configuration is the most stable structure among them. In addition, we also discuss the changes of the atom magnetic moments at interface and subinterface layers with respect to the corresponding bulk values.%56