Epitaxial Growth of Quasi-One-Dimensional Bismuth-Halide Chains with Topological Non-Trivial Edge States

TL;DR

This paper reports the epitaxial growth of quasi-one-dimensional Bi4I4 nanoribbons on Bi(111) surfaces, demonstrating topologically non-trivial edge states that are robust and observable, advancing the development of dissipationless electronic channels.

Contribution

It presents the first direct observation and verification of topological edge states in Bi4I4 nanoribbons grown epitaxially on Bi(111) surfaces.

Findings

Topological edge states are observed at the nanoribbon edges.

The edge states are robust against non time-reversal symmetry perturbations.

Theoretical simulations confirm the non-trivial topological nature of the edge states.

Abstract

Quantum spin Hall insulators have one-dimensional (1D) spin-momentum locked topological edge states (ES) inside the bulk band gap, which can serve as dissipationless channels for the practical applications in low consumption electronics and high performance spintronics. However, the clean and atomically sharp ES serving as ideal 1D conducting channels are still lack. Here, we report the formation of the quasi-1D Bi4I4 nanoribbons on the surface of Bi(111) with the support of the graphene-terminated 6H-SiC(0001) and the direct observations of the topological ES at the step edge by scanning tunneling microscopy and spectroscopic-imaging results. The ES reside surround the edge of Bi4I4 nanoribbons and exhibits remarkable robustness against non time reversal symmetry perturbations. The theoretical simulations verify the topological non-trivial character of 1D ES, which is retained after considering the presence of the underlying Bi(111). Our study supports the existence of topological ES in Bi4I4 nanoribbons, paving the way to engineer the novel topological features by using the nanoribbons as the 1D building block.