Tuning topological hinge states of Bi by edge adsorption: first-principles study

Recent studies have shown that bismuth is a crystalline topological insulator and, additionally, hosts two different second-order band topologies that are protected by twofold and the threefold rotational symmetries [1,2]. These second-order topologies manifest themselves in one-dimensional hinge states in samples whose shape preserve the corresponding rotational symmetry [1,2]. Using first-principles calculations we show that the hinge states can be significantly tuned by H and N adsorption. We discuss the changes in their dispersion curves, real-space charge distributions and spin texture. Our findings may have practical applications in future electronic devices.
1. H. Hsu et al., PNAS 116, 13255 (2019).
2. F. Schindler et al., Nature Phys. 14, 918 (2018).