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arXiv · 2505.02995

Coexisting topological hinges and 1D Rashba states in Bi$_{0.97}$Sb$_{0.03}$ revealed by the Josephson effect

Biplab Bhattacharyya·Stijn R. de Wit·Zhen Wu·Yingkai Huang·Mark S. Golden·Alexander Brinkman·Chuan Li
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Abstract

Second-order topological insulating (SOTI) states in three-dimensional materials are helical one-dimensional hinge states. Inducing superconductivity in these states leads to gapless bound states, characterized by the 4$\pi$-periodic current-phase relation. Here, we provide evidence of the topologically protected hinge states in Dirac semimetal Bi$_{0.97}$Sb$_{0.03}$ nanoflakes by an unconventional interference pattern in a magnetic field, and the 4$\pi$-periodic supercurrent carried by these states via the suppressed first and third Shapiro steps. Tight-binding simulations confirm the presence of multiple hinge modes, supporting our interpretation of Bi$_{0.97}$Sb$_{0.03}$ as a prototypical designable SOTI platform. Quantum confinement effect is identified by a quasi-one-dimensional bulk transport, and the confined Rashba states are responsible for the broadened hinge states.

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Biplab Bhattacharyya, Stijn R. de Wit, Zhen Wu, Yingkai Huang, Mark S. Golden, Alexander Brinkman, Chuan Li. 2025-05-05. Coexisting topological hinges and 1D Rashba states in Bi$_{0.97}$Sb$_{0.03}$ revealed by the Josephson effect. https://arxiv.org/abs/2505.02995

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