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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/2508.12841 |
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| _version_ | 1866909740644171776 |
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| author | Li, Wei Philipsen, Pier Brumme, Thomas Heine, Thomas |
| author_facet | Li, Wei Philipsen, Pier Brumme, Thomas Heine, Thomas |
| contents | Quantum spin Hall edge transport in two-dimensional transition-metal dichalcogenides depends on whether their one-dimensional edge channels are preserved under realistic substrates and device boundaries. Here we implement spin-orbit coupling in DFTB and GFN-xTB within the Amsterdam Modeling Suite, and apply it to 1T$'$/2H WSe$_2$ heterostructures. Edge-projected spectra reveal robust edge states in 1T$'$ ribbons; and these states remain robust against a laterally infinite 2H substrate, which only shifts the Dirac point via long-wavelength corrugation without introducing additional in-gap states. By contrast, terminated 2H edges generate trivial dispersion branches in the same energy window that hybridize only weakly with the topological edge modes. In the bulk, Fermi-level states are 1T$'$-derived; at the small twist angle, lattice-relaxation-induced strain drives miniband reconstruction, whereas at the large twist angle, the layers become electronically decoupled. These findings suggest the conditions -- controlled twist angle and avoidance of terminated 2H edges -- for achieving quantized conductance and unambiguous spectroscopic |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_12841 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Edge-state competition in a 2D topological insulator-semiconductor heterostructure Li, Wei Philipsen, Pier Brumme, Thomas Heine, Thomas Mesoscale and Nanoscale Physics Materials Science Quantum spin Hall edge transport in two-dimensional transition-metal dichalcogenides depends on whether their one-dimensional edge channels are preserved under realistic substrates and device boundaries. Here we implement spin-orbit coupling in DFTB and GFN-xTB within the Amsterdam Modeling Suite, and apply it to 1T$'$/2H WSe$_2$ heterostructures. Edge-projected spectra reveal robust edge states in 1T$'$ ribbons; and these states remain robust against a laterally infinite 2H substrate, which only shifts the Dirac point via long-wavelength corrugation without introducing additional in-gap states. By contrast, terminated 2H edges generate trivial dispersion branches in the same energy window that hybridize only weakly with the topological edge modes. In the bulk, Fermi-level states are 1T$'$-derived; at the small twist angle, lattice-relaxation-induced strain drives miniband reconstruction, whereas at the large twist angle, the layers become electronically decoupled. These findings suggest the conditions -- controlled twist angle and avoidance of terminated 2H edges -- for achieving quantized conductance and unambiguous spectroscopic |
| title | Edge-state competition in a 2D topological insulator-semiconductor heterostructure |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2508.12841 |