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| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2511.16165 |
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| _version_ | 1866911277367951360 |
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| author | Tan, Peng Chen, Yuantao Zhang, Yuqi Cheng, Hanyan Xian, Guoyu Cheng, Ming Sun, Minghong Yin, Jiaxin Wang, Feifan Wang, Yaxian Liu, Yanjun Huang, Mingyuan Wang, Zhiwei Yao, Yugui Meng, Sheng Huang, Li Dai, Yanan |
| author_facet | Tan, Peng Chen, Yuantao Zhang, Yuqi Cheng, Hanyan Xian, Guoyu Cheng, Ming Sun, Minghong Yin, Jiaxin Wang, Feifan Wang, Yaxian Liu, Yanjun Huang, Mingyuan Wang, Zhiwei Yao, Yugui Meng, Sheng Huang, Li Dai, Yanan |
| contents | Precise and ultrafast control of electronic band structures is a central challenge for advancing quantum functional materials and devices. Conventional approaches--such as chemical doping, lattice strain, or external gating--offer robust stability but remain confined to the quasi-static regime, far from the intrinsic femto- to picosecond dynamics that govern many-body interactions. Here, using cryogenic transient reflectance spectroscopy, we realize dynamic bandgap engineering in the anisotropic topological insulator $α$-Bi$_4$Br$_4$ with unprecedented micro-electron-volt ($μ$eV) precision. The exceptional sensitivity arises from the cooperative action of long-lived topological carriers, stabilized by restricted bulk-to-edge scattering phase space, together with symmetry-resolved coherent phonons that modulate inter-chain hopping. These channels jointly modify Coulomb screening and interband transitions, enabling both gradual and oscillatory control of the electronic structure. Supported by first-principles and tight-binding theory, we further demonstrate a dual-pump coherent control strategy for continuous, mode-selective tuning of electronic energies with $μ$eV accuracy. This framework paves the way for ultrafast on-demand band-structure engineering, pointing toward new frontiers in quantum optoelectronics, precision measurement in molecular and biological systems, and attosecond control of matter. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_16165 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Ultrafast μeV-Precision Bandgap Engineering in Low-Dimensional Topological Insulators Tan, Peng Chen, Yuantao Zhang, Yuqi Cheng, Hanyan Xian, Guoyu Cheng, Ming Sun, Minghong Yin, Jiaxin Wang, Feifan Wang, Yaxian Liu, Yanjun Huang, Mingyuan Wang, Zhiwei Yao, Yugui Meng, Sheng Huang, Li Dai, Yanan Mesoscale and Nanoscale Physics Precise and ultrafast control of electronic band structures is a central challenge for advancing quantum functional materials and devices. Conventional approaches--such as chemical doping, lattice strain, or external gating--offer robust stability but remain confined to the quasi-static regime, far from the intrinsic femto- to picosecond dynamics that govern many-body interactions. Here, using cryogenic transient reflectance spectroscopy, we realize dynamic bandgap engineering in the anisotropic topological insulator $α$-Bi$_4$Br$_4$ with unprecedented micro-electron-volt ($μ$eV) precision. The exceptional sensitivity arises from the cooperative action of long-lived topological carriers, stabilized by restricted bulk-to-edge scattering phase space, together with symmetry-resolved coherent phonons that modulate inter-chain hopping. These channels jointly modify Coulomb screening and interband transitions, enabling both gradual and oscillatory control of the electronic structure. Supported by first-principles and tight-binding theory, we further demonstrate a dual-pump coherent control strategy for continuous, mode-selective tuning of electronic energies with $μ$eV accuracy. This framework paves the way for ultrafast on-demand band-structure engineering, pointing toward new frontiers in quantum optoelectronics, precision measurement in molecular and biological systems, and attosecond control of matter. |
| title | Ultrafast μeV-Precision Bandgap Engineering in Low-Dimensional Topological Insulators |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2511.16165 |