Inelastic Scattering and Secondary Electron Emission under Resonance Conditions in RHEED from Pt(111)

Abstract

The discovery of scattering resonances in Reflection High Energy Electron Diffraction (RHEED) dates back to 1933 when Kikuchi and Nakagawa [1] observed an anomalous enhancement of diffraction intensities from ZnS under certain experimental conditions. Miyake et al. [2] recognized these conditions to be fulfilled whenever a diffracted beam, just before emergence from the crystal, is propagating nearly parallel to the surface. Kohra et al. [3] showed that this situation corresponds to the existence of an intense wavefield at the surface of the crystal which is stationary and strongly damped into the crystal. Miyake and Hayakawa [4] were the first who suggested that the effect is based on a resonant scattering process (involving a surface state of the crystal). Many references have been made to this paper using terms such as “surface state resonance”, “surface wave resonance” or “surface resonance” to denote the effect. However, the origin and nature of the resonant states concerned have been clarified only recently. With the aid of model calculations based on a multislice formulation of the RHEED theory [5] it has been shown that these states correspond to the intrinsic bound states in the scattering potential of an atomic monolayer [6,7].