Direct Visualization of Room-temperature Stair-stepped Quantum Spin Hall States in Bi4Br4
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arXiv
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| Autori principali: | , , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| _version_ | 1866910017742962688 |
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| author | Hu, Zhiqiang Zhang, Yuqi Wang, Yuyang Xiao, Kebin Li, Xiang Wang, Zhiwei Yang, Huaixin Yao, Yugui Xue, Qi-Kun Li, Wei |
| author_facet | Hu, Zhiqiang Zhang, Yuqi Wang, Yuyang Xiao, Kebin Li, Xiang Wang, Zhiwei Yang, Huaixin Yao, Yugui Xue, Qi-Kun Li, Wei |
| contents | Topological insulators host exotic quantum phenomena such as the quantum spin Hall (QSH) effect, which enables dissipationless one-dimensional edge conduction. Realizing such states at room temperature and on a macroscopic scale is essential for energy-efficient electronics and quantum technologies, yet remains a fundamental challenge due to material limitations. Here, using microwave impedance microscopy, we directly visualize robust QSH states persisting up to 300 K in α-Bi4Br4 nanowires. This stability and scalability are enabled by a stair stepped stacking configuration, a multilayer geometry in which QSH edge states from individual layers remain spatially decoupled. This configuration circumvents the stringent alignment and layer number constraints of previous proposals, allowing robust stair-stepped QSH (SS-QSH) conduction in structures several micrometers long and hundreds of nanometers high. Magnetic field and temperature dependent measurements confirm their intrinsic topological nature. Crucially, the SS-QSH and bulk signals scale with nanowire height, verifying the stair stepped origin. Our results are also successfully reproduced by finite-element analysis simulations. This work establishes α Bi4Br4 as a practical platform for high temperature topological electronics and demonstrates a generalizable stacking strategy for designing scalable QSH systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2602_09660 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Direct Visualization of Room-temperature Stair-stepped Quantum Spin Hall States in Bi4Br4 Hu, Zhiqiang Zhang, Yuqi Wang, Yuyang Xiao, Kebin Li, Xiang Wang, Zhiwei Yang, Huaixin Yao, Yugui Xue, Qi-Kun Li, Wei Mesoscale and Nanoscale Physics Materials Science Topological insulators host exotic quantum phenomena such as the quantum spin Hall (QSH) effect, which enables dissipationless one-dimensional edge conduction. Realizing such states at room temperature and on a macroscopic scale is essential for energy-efficient electronics and quantum technologies, yet remains a fundamental challenge due to material limitations. Here, using microwave impedance microscopy, we directly visualize robust QSH states persisting up to 300 K in α-Bi4Br4 nanowires. This stability and scalability are enabled by a stair stepped stacking configuration, a multilayer geometry in which QSH edge states from individual layers remain spatially decoupled. This configuration circumvents the stringent alignment and layer number constraints of previous proposals, allowing robust stair-stepped QSH (SS-QSH) conduction in structures several micrometers long and hundreds of nanometers high. Magnetic field and temperature dependent measurements confirm their intrinsic topological nature. Crucially, the SS-QSH and bulk signals scale with nanowire height, verifying the stair stepped origin. Our results are also successfully reproduced by finite-element analysis simulations. This work establishes α Bi4Br4 as a practical platform for high temperature topological electronics and demonstrates a generalizable stacking strategy for designing scalable QSH systems. |
| title | Direct Visualization of Room-temperature Stair-stepped Quantum Spin Hall States in Bi4Br4 |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2602.09660 |