From K atom pairs to K atomic chains: A semiconducting 2x3 to metallic 2x1 transition on the beta-SiC(100) c(4x2) surface

[[abstract]]We study the K/beta-SiC(100) c(4x2) surface by atom-resolved scanning tunneling microscopy and spectroscopy, and synchrotron radiation-based photoemission spectroscopy. At intermediate coverages, the K atoms are grouped by pairs around Si dimers at pedestal sites, in a 2x3 long-range ordering leaving 1/3 of the pedestal sites unoccupied, while keeping the semiconducting c(4x2) surface unchanged as identified by tunneling through the K overlayer. At saturation, additional K atoms adsorb on remaining pedestal sites and act as atomic "contacts" between two K pairs, leading to K atom chain formation in a 2x1 metallic surface.[[fileno]]2060117010098[[department]]工程與系統科學