First-principle study of the atomic structure and magnetic properties of ultrathin Ni films on Cu(001) substrate

Atomic structures and magnetic properties of ultrathin Ni films on the Cu(0 01) substrate are studied by using the full potential linearized augmented plane wave (FLAPW) method with generalized-gradient approximation (GGA) for the exchange correlation interactions. Unlike the uniform structure relaxa tions found in a recent LEED measurement, the Ni-Ni interlayer distances st rongly vary in depth with relaxations of -8, 1.1 and -1.7% from the surface to the interface in Ni-4/Cu(001) compared to that in the bulk Ni (1.76 Ang strom). Interestingly, uniform relaxations are found in Cu-2/Ni-4/Cu(001), indicating a possible subsurface growth mode in these systems. The spin and orbital magnetic moments of Ni atoms increase at the surface and decrease at the interface. (C) 2000 Elsevier Science B.V. All rights reserved.