Electronic transition of Au-induced atomic chains onSi(5 5 12): A strong similarity with theAu∕Si(5 5 7)system

Abstract

We investigated in detail the electronic structures of the $\text{Si}(5 5 12)$ surface with Au adsorbates, which features one-dimensional (1D) atomic chains and a 1D metallic band. From angle-resolved UV photoelectron spectroscopy, we resolved that the nearly half-filled 1D band is actually composed of two parallel branches; one is metallic, but the other is insulating with an energy gap of $50\phantom{\rule{0.3em}{0ex}}\text{meV}$ below ${E}_{F}$ at room temperature. An energy gap evolves gradually from $270\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ on the metallic branch, saturating at $75\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ with a size of $40\phantom{\rule{0.3em}{0ex}}\text{meV}$ below ${E}_{F}$, while the insulating branch is intact. These behaviors are essentially identical with those recently reported on the $\text{Au}∕\text{Si}(5 5 7)$ system [Phys. Rev. Lett. 91, 196403 (2003)]. The scanning tunneling microscopy imaging indicates that these surfaces possess common 1D atomic chain structures, while the interchain distance is different. This explains the very similar electronic structure and transition of the two systems.