Robust topological edge states at the perfect surface step edge of topological insulator ZrTe$_5$

摘要

We report an atomic-scale characterization of ZrTe$_5$ by using scanningtunneling microscopy. We observe a bulk bandgap of ~80 meV with topologicaledge states at the step edge, and thus demonstrate ZrTe$_5$ is a twodimensional topological insulator. It is also found that an applied magneticfield induces energetic splitting and spatial separation of the topologicaledge states, which can be attributed to a strong link between the topologicaledge states and bulk topology. The perfect surface steps and relatively largebandgap make ZrTe$_5$ be a potential candidate for future fundamental studiesand device applications.