Auger mediated quantum sticking of positrons to surfaces: Evidence for single step transition from a scattering state to a surface image potential bound state

We present the observation of an efficient mechanism for positron sticking to surfaces termed here Auger mediated quantum sticking. In this process the energy associated with the positrons transition from an unbound scattering state to a bound image potential state is coupled to a valence electron which can then have sufficient energy to leave the surface. Compelling evidence for this mechanism is found in a narrow secondary electron peak observed at incident positron kinetic energies well below the electron work function.