Towards Layer-Selective Quantum Spin Hall Channels in Weak Topological Insulator Bi4Br2I2

Abstract

Weak topological insulators, constructed by stacking quantum spin Hall insulators with weak interlayer coupling, offer promising quantum electronic applications through topologically nontrivial edge channels. However, the currently available weak topological insulators are stacks of the same quantum spin Hall layer with translational symmetry in the out-of-plane direction, leading to the absence of the channel degree of freedom for edge states. Here, we study a candidate weak topological insulator, Bi4Br2I2, which is alternately stacked by three different quantum spin Hall insulators, each with tunable topologically non-trivial edge states. Our angle-resolved photoemission spectroscopy and first-principles calculations show that an energy gap opens at the crossing points of different Dirac cones correlated with different layers due to the interlayer interaction. This is essential to achieve the tunability of topological edge states as controlled by varying the chemical potential. Our work offers a perspective for the construction of tunable quantized conductance devices for future spintronic applications.

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Cited by in corpus (9)

• Topological electronic structure and spin texture of quasi-one-dimensional higher-order topological insulator Bi4Br4
• Altermagnetism-Induced Parity Anomaly in Weak Topological Insulators
• Coalescence of multiple topological orders in quasi-one-dimensional bismuth halide chains
• Topological Phase Transition in Quasi-One-Dimensional Bismuth Iodide Bi4I4
• Mass Acquisition of Dirac Fermions in Bi4I4 by Spontaneous Symmetry Breaking
• Intertwined topological phases in TaAs2 nanowires with giant magnetoresistance and quantum coherent surface transport
• Origin of Robust ${\mathbb{Z}}_2$ Topological Phases in Stacked Hermitian Systems: Non-Hermitian Level Repulsion
• Phonons Drive the Topological Phase Transition in Quasi-One-Dimensional Bi${}_4$I${}_4$
• Zero Indirect Band Gap and Flat Bands in a Niobium Oxyiodide Cluster Material