Bismuth-Induced Nanostructures on III-V Semiconductor Surfaces with Non-Trivial Topological Properties

Bismuth-containing III-V semiconductor alloys receive strong attention for various applications within optoelectronics. Furthermore, their large spin-orbit splitting and predicted non-trivial topological properties are promising for application in spintronics and quantum computation, even at room temperature [1,2]. However, bulk growth is challenging and III-V alloys with more than 20% Bi content have not been realized yet.

Here, we will present III-V semiconductor structures with high Bi content, obtained through Bi deposition onto different GaAs [2,3] and InSb surfaces, resulting in the formation of ordered 1D and 2D nanostructures of high Bi content, investigated by scanning tunneling microscopy and spectroscopy (STM/S), X-ray photoelectron spectroscopy (XPS), and angle-resolved XPS (ARPES).

Upon Bi deposition on GaAs(111)B at elevated sample temperature, we find the formation of a honeycomb surface structure of Bi atoms. In contrast to conventional Bismuthene, these Bi atoms have strong covalent bonds to the As atoms of the underlying GaAs, but only weak bonds between each other. According to density functional theory calculations, this opens a large inverted band gap.

Bi deposition onto InSb(111)A and InSb(110) results in well-ordered 2D and 1D surface structures, respectively, where STS reveals Bi-induced confined states in the III-V band gap and ARPES indicates strong Rashba splitting as well as Bi-induced bands crossing the Fermi level.



[1] Chuang et al, Nano Lett. 14, 2505 (2014).