Stability of a nonequilibrium phase in an immiscible Ag-Ni system studied byab initiocalculations and ion-beam-mixing experiment

Employing the Vienna ab initio simulation package (VASP), a possible nonequilibrium intermediate state located near Ag₃Ni in the immiscible Ag-Ni system is predicted through calculating the total energy of six possible structures of A₃B type as a function of their lattice constants. The predicted state is confirmed by the fact that a metastable hcp Ag₃Ni phase was indeed obtained in the properly designed Ag-Ni multilayers upon 200 keV xenon ion irradiation at 77 K and its lattice constants determined by diffraction analysis were in good agreement with the calculated values.