MOVING GOLD ATOMS WITH AN ATOMIC-FORCE-MICROSCOPE TIP - A STUDY OF DIMER AND TRIMER FORMATION ON NACL(100)

Recently it was demonstrated that the manipulation of atoms with the tip apex of a scanning probe microscope is a promising tool for the fabrication of nanometer-scale structures. We report time-dependent calculations of the motion of gold atoms on the NaCl(100) surface occurring after the collision with the tip of an atomic-force microscope (AFM). The interaction between the adsorbates and the tip-sample junction is calculated by considering a summation of pairwise potentials. The time-dependent trajectories of the adsorbed species are then derived from a classical dynamical dissipative method. Within this framework, the possibility of moving a single gold atom is investigated. We have also studied the formation of gold dimers and trimers from such manipulations. The stability of such clusters is discussed, in particular, its dependence on the initial position of the AFM tip. The range of tip-surface distances, which allows a controlled manipulation, has been determined,