Observation of a threshold in potential sputtering of LiF surfaces

A quartz-crystal microbalance technique is used for measuring total sputter ing yields for LiF under impact of slow (20 eV, 100 eV, 500 eV and 1000 eV kinetic energy) singly and doubly charged ions. At low kinetic energies (le ss than or equal to 100 eV) potential sputtering (PS) (i.e., sputtering due to the projectiles potential energy) clearly dominates over kinetically in duced sputtering. New insight into the mechanisms for PS is gained by deter mining the minimum potential energy necessary to induce PS. The measured po tential energy threshold at around 10 eV provides evidence that PS can alre ady be induced by the production of cold holes in the valence band of LiF v ia resonant neutralisation. (C) 2000 Elsevier Science B.V. All rights reser ved.