Topological domain-wall states from Umklapp scattering in twisted bilayer graphene
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866914199143186432 |
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| author | Li, Juncheng Chen, Cong Yao, Wang |
| author_facet | Li, Juncheng Chen, Cong Yao, Wang |
| contents | Twistronics, harnessing interlayer rotation to tailor electronic states in van der Waals materials, has predominantly focused on small-angle regime. Here, we unveil the pivotal role of intervalley Umklapp scattering in large-angle twisted bilayer graphene, which governs low-energy physics and drives unconventional band topology. By constructing symmetry-constrained effective $k\cdot p$ models for $\pm 21.8^{\circ}$-twisted bilayers, we demonstrate how structural chirality imprints distinct electronic responses. The $D_6$ configuration exhibits a gapped spectrum with chiral interlayer coupling, while $D_3$ symmetric stacking configuration displays semimetallic behavior. Crucially, chirality inversion creates topological domain-wall states, which manifest as counterpropagating pseudospin modes at interfaces between oppositely twisted regions. These states, absent in untwisted bilayers, emerge from a Jackiw-Rebbi-like mechanism tied to chirality reversal. Atomistic simulations confirm these topological states and demonstrate their robustness against symmetry-breaking perturbations. The interplay between twist-induced chirality and topology opens new pathways for engineering domain-wall states in twisted materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_03761 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Topological domain-wall states from Umklapp scattering in twisted bilayer graphene Li, Juncheng Chen, Cong Yao, Wang Mesoscale and Nanoscale Physics Materials Science Twistronics, harnessing interlayer rotation to tailor electronic states in van der Waals materials, has predominantly focused on small-angle regime. Here, we unveil the pivotal role of intervalley Umklapp scattering in large-angle twisted bilayer graphene, which governs low-energy physics and drives unconventional band topology. By constructing symmetry-constrained effective $k\cdot p$ models for $\pm 21.8^{\circ}$-twisted bilayers, we demonstrate how structural chirality imprints distinct electronic responses. The $D_6$ configuration exhibits a gapped spectrum with chiral interlayer coupling, while $D_3$ symmetric stacking configuration displays semimetallic behavior. Crucially, chirality inversion creates topological domain-wall states, which manifest as counterpropagating pseudospin modes at interfaces between oppositely twisted regions. These states, absent in untwisted bilayers, emerge from a Jackiw-Rebbi-like mechanism tied to chirality reversal. Atomistic simulations confirm these topological states and demonstrate their robustness against symmetry-breaking perturbations. The interplay between twist-induced chirality and topology opens new pathways for engineering domain-wall states in twisted materials. |
| title | Topological domain-wall states from Umklapp scattering in twisted bilayer graphene |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2508.03761 |