Energy loss of MeV light ions specularly reflected from a SnTe(001) surface

Energy losses of specularly reflected MeV protons and He ions from a clean (001) surface of SnTe single crystal are observed. The position-dependent stopping powers near the surface are derived from the observed results. The obtained stopping power is proportional to E^-1/2 exp(-β₃x/2aTF), where E is the ion energy, aTF is the Thomas-Fermi screening distance, β₃ is 0.3, and x is the distance from the surface. This result is similar to the observed position-dependent stopping power for planar channeled ions.