Structural and electronic properties of atomically thin Bismuth on Au(111)

Atomically thin Bismuth (Bi) films are predicated to be candidates for high temperature quantum spin hall materials. Here, we reported the structural evolutions and the corresponding electronic properties of Bi ultrathin films on Au(111) at initial stage as a function of coverage using low-energy electron diffraction (LEED), scanning tunneling microscopy (STM) and photoemission spectroscopy (PES). The small window for a stable two dimensional (2D) Bi in Kagome and honeycomb lattice on Au(111) has been optimized. LEED and STM results show that Bi atoms self-assemble into dimered (5 x 5) superdots, (root 37 x root 37)R25. 3 degrees in a Kagome lattice and (p x root 3) stripes sequentially in the first monolayer regime and into bi-layered Bi (110) islands afterwards. UPS results show the disappearance of Au(111) surface states at coverage of 0.18 ML, revealing the Van der Waals interactions between Au(111) and Bi adatoms. The repulsive interactions between Bi atoms prevent the 2D Bi structure from islands forming at initial stage and benefit large domains in (root 37 x root 37)R25. 3 degrees Kagome lattice. Such 2D Bi may be interesting because of its relevance in terms of novel physical properties.