The electron reflection amplitude R at stacking-fault (SF) induced fractional steps is determined for Ag(111) surface states using a low temperature scanning tunneling microscope. Unexpectedly, R remains as high as 0.6∼0.8 as energy increases from 0 to 0.5 eV, which is in clear contrast to its rapidly decreasing behavior for monatomic (MA) steps [L. B{\"u}rgi et al., Phys. Rev. Lett. \textbf{81}, 5370 (1998)]. Tight-binding calculations based on {\em ab-initio} derived band structures confirm the experimental finding. Furthermore, the phase shifts at descending SF steps are found to be systematically larger than counterparts for ascending steps by ≈0.4π. These results indicate that the subsurface SF plane significantly contributes to the reflection of surface states.
@article{arxiv.1005.1113,
title = {Strong Electron Confinement By Stacking-fault Induced Fractional Steps on Ag(111) Surfaces},
author = {Takashi Uchihashi and Katsuyoshi Kobayashi and Tomonobu Nakayama},
journal= {arXiv preprint arXiv:1005.1113},
year = {2015}
}