The electron-reflection amplitude R at stacking-fault-induced fractional steps was determined for Ag(111) surface states using a low-temperature scanning tunnelling microscope. Unexpectedly, R remains as high as 0.6 to 0.7 as the energy increased from 0 to 0.5eV, which was in clear contrast to its rapidly decreasing behavior for monatomic steps (Bürgi et al., 1998). Tight-binding calculations based on ab initio derived band structures confirmed the experimental finding. The result could be explained by a significant contribution of the sub-surface stacking-fault plane to the reflection of surface states.

Strong Electron Confinement by Stacking-Fault-Induced Fractional Steps on Ag(111) Surfaces. T.Uchihashi, K.Kobayashi, T.Nakayama: Physical Review B, 2010, 82[11], 113413