Generation and stability of metal clusters generated with the EC-STM

M. M. MARISCAL; M. G. DEL PÓPOLO; E. P. M. LEIVA; W. SCHMICKLER

High Temperature Society of Japan

High Temperature Society of Japan

Año: 2002 p. 260 - 260

0387-1096

he scanning tunneling microscope (STM), operated in an electrochemical cell, offers a cheap and precise way of generating metal clusters on a foreign metal substrate: the metal is first deposited on the STM tip, then the tip is brought into contact with the electrode surface, and subsequently withdrawn. In several systems, such as Cu clusters on Au(111) or Pd on Au(111), this method produces stable clusters, while in others, such as Cu on Ag(111), it does not. In order to explore the fundamentals of this process, we have simulated the deposition of the clusters in a microcanonical molecular dynamics simulation, using embedded atom potentials for the interactions. In those cases were cluster formation was observed, we studied their stability by a grand-canonical Monte Carlo simulation, in which the chemical potential, and hence the electrode potential, can be varied. We observed stable clusters only in those cases in which the two metals form stable alloys. Our results also e