Coexisting Massive and Massless Dirac Fermions in Moire'-Reconstructed Bilayer Graphene
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866918394722254848 |
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| author | Jat, Mohit Kumar Watanabe, Kenji Taniguchi, Takashi Bid, Aveek |
| author_facet | Jat, Mohit Kumar Watanabe, Kenji Taniguchi, Takashi Bid, Aveek |
| contents | We report the emergence of massless Dirac fermions in moiré-reconstructed bands of bilayer graphene (BLG) aligned with hexagonal boron nitride (hBN). Magnetotransport measurements reveal that while the primary BLG band retains a parabolic dispersion with a Berry phase of $2π$, the moiré-induced secondary bands at $n/n_0 = \pm 4$ host chiral massless quasiparticles with a Berry phase $π$ and a Fermi velocity $v_m \approx 3.6 \times 10^5 \mathrm{m s^{-1}}$. This transition from massive to massless carriers arises from topological band reconstruction driven by the hBN moiré potential. Our results demonstrate that moiré engineering in BLG/hBN offers a powerful route to tune band topology and realize coexisting Dirac and massive fermions within a single crystalline platform. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_20309 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Coexisting Massive and Massless Dirac Fermions in Moire'-Reconstructed Bilayer Graphene Jat, Mohit Kumar Watanabe, Kenji Taniguchi, Takashi Bid, Aveek Mesoscale and Nanoscale Physics Materials Science We report the emergence of massless Dirac fermions in moiré-reconstructed bands of bilayer graphene (BLG) aligned with hexagonal boron nitride (hBN). Magnetotransport measurements reveal that while the primary BLG band retains a parabolic dispersion with a Berry phase of $2π$, the moiré-induced secondary bands at $n/n_0 = \pm 4$ host chiral massless quasiparticles with a Berry phase $π$ and a Fermi velocity $v_m \approx 3.6 \times 10^5 \mathrm{m s^{-1}}$. This transition from massive to massless carriers arises from topological band reconstruction driven by the hBN moiré potential. Our results demonstrate that moiré engineering in BLG/hBN offers a powerful route to tune band topology and realize coexisting Dirac and massive fermions within a single crystalline platform. |
| title | Coexisting Massive and Massless Dirac Fermions in Moire'-Reconstructed Bilayer Graphene |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2510.20309 |