Self-assembled 1D nanostructures on semiconductor surfaces

Self-assembled one-dimensional (1D) nanostructures have attracted considerable attention in the last decades
since their low dimensional architecture offers the possibility to realize atomically precise patterns on
semiconducting surfaces. Moreover, the gapped substrate allows the study of the exotic properties of the 1D
physics. Bismuth nanolines and their derived Haiku structure are, in this scenario, a unique 1D structures self-
assembled on the Si(001) surface. They can grow several micrometers long, almost defect free, in dense arrays or
isolated. Their length and tunable density make them suitable for realizing large area functionalized patterns.
Although these systems were deeply investigated over the years, their electronics structures have yet not well
understood.
Here, an STM/STS study combined with DFT simulation of the electronic properties of the Bi nanolines and
derived Haiku structures is presented. High-resolution STM micrographs reveal a rich variety of periodic electronic
features as a function of bias voltage. The atomic structures of Bi nanolines and the interplay between Bi and the
Si substrate, essential to understanding the electronic and transport properties, are investigated in great details
and reproduced in good agreement by the DFT simulations.