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

A recent experimental study indicates that full-Heusler alloy Co2VGa exhibits half-metallic ferromagnetism and the magnetic moment measured at 5 K is independent of high pressure up to 12.1 kbar [T. Kanomata et al. Phys. Rev. B 82, 144415 (2010)]. Using the full potential linearized augmented plane-wave method, we here further investigate the structural, electronic, and magnetic properties of all possible (111) surfaces of Co2VGa. Both structural relaxation and calculated surface energy reveal that Ga-terminated surface is more stable than other terminations. From the analysis of the spin-polarized density of states, we find that the half-metallicity confirmed in bulk Co2VGa is lost at the Co-terminated surface but still maintained at the V- and Ga-terminated surfaces. Moreover, we also find that the atomic magnetic moments at the (111) surfaces are greatly different from the bulk values.