THE EFFECTS OF THE ELECTRIC-FIELD IN THE STM ON EXCITATION LOCALIZATION - IMPLICATIONS FOR LOCAL BOND BREAKING

We discuss the effects of the electric field present in the STM on the frequency and spatial localization of (vibrational) excitations induc ed by inelastic electron tunneling. We show that, depending on its dir ection and size, the held can produce either a weakening or a strength ening of chemical bonds. The resulting vibrational frequency shifts co uld lead to the localization of the excitation under the STM tip, redu cing energy transfer rates to surrounding sites by several orders of m agnitude. This localization gives the STM the ability to locally activ ate surface dynamical processes, and induce atomic-scab modification o f materials.