Identification of intermediate linear structure formed during Bi/Si(0 0 1) surface anneal

Bi nanolines form at around 570 °C during the anneal of a Bi-rich surface, which is composed of a mixture of Bi dimers, Si dimers, and missing dimer defects. High-temperature STM observations find that as well as the stable nanolines previously reported, a second Bi-related linear feature forms in the background, which has not previously been identified. Using quench experiments, and by comparison with tightbinding simulations of candidate surface structures, the structure of this linear feature has been identified. It is concluded that the linear defective feature comprises a single missing dimer defect (1DV) decorated with Bi, and forms as a result of cooperative strain relaxation between the Bi dimers and the 1DV.