Electronic Structure of Cu-Ni Alloys

Band structures of three ordered Cu-Ni alloys are calculated by the Green's function method. These are Cu 3 Ni, CuNi 3 and CuNi. The density-of-states of Cu 3 Ni has a remarkable character. There appears a narrow and high band in the high energy region. It is separated from the main band, but it is still below the Fermi energy. By using the tightbinding approximation we also calculate the density-of-states of the ordered alloys Cu 6 Ni 2 and Cu 5 Ni 3 . The density-of-states obtained for these alloys are compared with those of disordered Cu-Ni alloys of the same concentration. The latter is evaluated by CPA. The density-of-states of the Cu-rich disordered alloys is quite similar to that of the ordered alloy of the same Ni-concentration, although the fine structures in the density-of-states are washed out in the disordered state.