Surface-induced magnetism in intermetallics: Ni3Ge compound as a case study

Abstract By means of the first-principles calculations we investigate the magnetic properties of four low-index surfaces in the bulk nonmagnetic Ni 3 Ge intermetallic compound with the L1 2 structure. We predict that the (1 1 1) surface of Ni 3 Ge is magnetically ordered, with all magnetic moments located at the Ni sites. Magnetic order is also found at the Ni-terminated (0 0 1), (1 1 0) and (2 1 0) surfaces, however, the nonmagnetic NiGe-terminated surfaces are more stable similarly as in other L1 2 compounds. It turns out that the magnetic order in the bulk Ni 3 Ge is destroyed completely by the hybridization of Ge- p and Ni- d states and it is recovered at some surfaces due to the reduced coordinate number of Ni atoms. We also report on a particular distribution of magnetization at the Ni 3 Ge(1 1 1) surface where the ferromagnetic and anti-ferromagnetic-like states are degenerated because there are magnetically dead layers between the two magnetic surfaces and there is no interference between them. The calculated results obtained for Ni 3 Ge are compared with those for Ni 3 Al; the differences between these two compounds are discussed.