Emergent $Z_2$ Topological Invariant and Robust Helical Edge States in Two-Dimensional Topological Metals

Abstract

In this work, we study the disorder effect on topological metals that support a pair of helical edge modes deeply embedded inside the gapless bulk states. Strikingly, we predict that a quantum spin Hall (QSH) phase can be obtained from such topological metals without opening a global band gap. To be specific, disorder can lead to a pair of robust helical edge states which is protected by an emergent $Z_2$ topological invariant, giving rise to a quantized conductance plateau in transport measurements. These results are instructive for solving puzzles in {various transport experiments on QSH materials} that are intrinsically metallic. This work also will inspire experimental realization of the QSH effect in disordered topological metals.

7 pages, 7 figures

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Cited by in corpus (3)

• Bulk-boundary correspondence in disordered higher-order topological insulators
• Chiral Interface States and Related Quantized Transport in Disordered Chern Insulators
• Evolution of Berry curvature and reentrant quantum anomalous Hall effect in an intrinsic magnetic topological insulator