Real-time STM study of inter-nanowire reactions: GdSi2 nanowires on Si(1Â 0Â 0)

We report the co-existence and growth of two different types of GdSi2 nanowires (NWs) following Gd deposition on the Si(1 0 0) surface. The first NW type is hexagonal and similar in appearance and orientation to that previously reported in the literature. The structure of the second NW type is unknown, but its orientation, thermodynamic stability and surface appearance are consistent with an orthorhombic structure. Real-time high-temperature STM studies show that these new NWs are thermodynamically preferred and in regions where both wires co-exist, they grow at the expense of their hexagonal counterparts. The implications of these observations for nanoscale interconnects is discussed.