Surface investigations using monolayer-resolvable high-resolution Rutherford backscattering spectroscopy

Energy spectra of scattered 0.5 MeV He ions from a clean (001) surface of SnTe are measured with a 90° sector magnetic spectrometer (ΔE/E 0.1%). The ions scattered from successive atomic layers can be resolved in the energy spectra. Inelastic energy losses and charge state distributions of 0.5 MeV He ions scattered from the topmost atomic layer of the SnTe(001) are measured. A position-dependent stopping power at the surface is proposed from the observed energy losses. The observed charge state distribution shows the importance of the charge-exchange processes with valence electrons in the tail of the electron distribution at the surface.