Interplay between adsorbate diffusion and electron tunneling at an insulating surface

We investigate electron tunneling between defects and mobile adsorbates on the surface of MgO and show that electrons can be transferred to Au and Pt atoms from defects, such as oxygen vacancies, over distances similar to 20 angstrom even at room temperature. As a result of the surface-mediated interaction following electron transfer, the mobility of these metal atoms is enhanced significantly. Such processes may affect the kinetics of growth and structure of adsorbed clusters and thin films and the interaction of molecules with surfaces.