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Coexisting Topological Hinges and 1D Rashba States in Bi0.97Sb0.03 Revealed by the Josephson Effect
Biplab Bhattacharyya1, Stijn R de Wit1, Zhen Wu1
1MESA+ Institute, University of Twente, Enschede7500 AE, The Netherlands.
ACS Nano
|August 11, 2026
Summary
Researchers observed unique superconducting properties in bismuth antimonide nanoflakes, revealing protected one-dimensional hinge states. This discovery advances the understanding of second-order topological insulators and their potential applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Topological Materials
Background:
- Second-order topological insulating (SOTI) states feature helical one-dimensional hinge states in 3D materials.
- Superconductivity in SOTI states can lead to gapless bound states with a 4π-periodic current-phase relation.
Purpose of the Study:
- To provide evidence for topologically protected hinge states in Dirac semimetal Bi0.97Sb0.03 nanoflakes.
- To investigate the superconducting properties and current-phase relation of these hinge states.
Main Methods:
- Experimental observation of unconventional interference patterns in a magnetic field.
- Measurement of suppressed first and third Shapiro steps to detect 4π-periodic supercurrent.
- Tight-binding simulations to confirm hinge modes and analyze transport properties.
Main Results:
- Evidence of topologically protected hinge states in Bi0.97Sb0.03 nanoflakes.
- Observation of a 4π-periodic supercurrent carried by these hinge states.
- Identification of quantum confinement effects and confined Rashba states contributing to broadened hinge states.
Conclusions:
- Bi0.97Sb0.03 serves as a prototypical platform for designing and studying SOTI states.
- The findings confirm the existence and unique superconducting behavior of hinge states in this material.
- This work deepens the understanding of topological quantum phenomena in condensed matter systems.
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