Chiral-helical junctions in screened graphene
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arXiv
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| Main Authors: | , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| _version_ | 1866912775627866112 |
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| author | Kousar, Bilal Franca, Selma Perconte, David Khvalyuk, Anton Yang, Wenmin Vignaud, Hadrien Gay, Frédéric Watanabe, Kenji Taniguchi, Takashi Winkelmann, Clemens B. Zhou, Yangtao Han, Zheng Vitto Assouline, Alexandre Bardarson, Jens H. Grushin, Adolfo G. Sellier, Hermann Sacépé, Benjamin |
| author_facet | Kousar, Bilal Franca, Selma Perconte, David Khvalyuk, Anton Yang, Wenmin Vignaud, Hadrien Gay, Frédéric Watanabe, Kenji Taniguchi, Takashi Winkelmann, Clemens B. Zhou, Yangtao Han, Zheng Vitto Assouline, Alexandre Bardarson, Jens H. Grushin, Adolfo G. Sellier, Hermann Sacépé, Benjamin |
| contents | Reproducibility and quantization in quantum spin Hall platforms is a persisting challenge, limiting their use in hybrid realizations of topological superconductivity. We report robust and reproducible quantized transport in a graphene quantum Hall topological insulator, stabilized at low magnetic fields by screening long-range Coulomb interactions with a metallic Bi$_2$Se$_3$ back gate. Beyond quantized resistance plateaus, we demonstrate mode-resolved control via gate-defined chiral-helical junctions that selectively transmit or backscatter a single helical channel, a capability inaccessible in time-reversal symmetric quantum spin Hall systems. Targeted experiments and simulations identify contact-induced doping, effectively creating unintended chiral-helical interfaces, as a generic mechanism for quantization breakdown, which is mitigated by large area contacts that enhance edge-channel equilibration. Our findings establish metal screened graphene as a gate-tunable, interaction-driven helical system with quantized transport, spatially separable helical channels, and compatibility with superconducting proximity for topological devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_13256 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Chiral-helical junctions in screened graphene Kousar, Bilal Franca, Selma Perconte, David Khvalyuk, Anton Yang, Wenmin Vignaud, Hadrien Gay, Frédéric Watanabe, Kenji Taniguchi, Takashi Winkelmann, Clemens B. Zhou, Yangtao Han, Zheng Vitto Assouline, Alexandre Bardarson, Jens H. Grushin, Adolfo G. Sellier, Hermann Sacépé, Benjamin Mesoscale and Nanoscale Physics Reproducibility and quantization in quantum spin Hall platforms is a persisting challenge, limiting their use in hybrid realizations of topological superconductivity. We report robust and reproducible quantized transport in a graphene quantum Hall topological insulator, stabilized at low magnetic fields by screening long-range Coulomb interactions with a metallic Bi$_2$Se$_3$ back gate. Beyond quantized resistance plateaus, we demonstrate mode-resolved control via gate-defined chiral-helical junctions that selectively transmit or backscatter a single helical channel, a capability inaccessible in time-reversal symmetric quantum spin Hall systems. Targeted experiments and simulations identify contact-induced doping, effectively creating unintended chiral-helical interfaces, as a generic mechanism for quantization breakdown, which is mitigated by large area contacts that enhance edge-channel equilibration. Our findings establish metal screened graphene as a gate-tunable, interaction-driven helical system with quantized transport, spatially separable helical channels, and compatibility with superconducting proximity for topological devices. |
| title | Chiral-helical junctions in screened graphene |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2512.13256 |