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

TL;DR

This paper reports the discovery of an efficient positron surface attachment process called Auger mediated quantum sticking, where positrons transition from scattering to bound states via electron interactions, evidenced by a specific electron emission peak.

Contribution

It introduces and provides experimental evidence for a novel positron surface attachment mechanism, expanding understanding of positron-surface interactions.

Findings

Observation of a narrow secondary electron peak at low positron energies.

Identification of Auger mediated quantum sticking as an efficient attachment process.

Evidence of a single-step transition from scattering to bound state.

Abstract

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.