Unconventional topological Weyl-dipole phonon
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
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2025
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| _version_ | 1866910842505658368 |
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| author | Wang, Jianhua Wang, Yang Zhou, Feng Wang, Wenhong Cheng, Zhenxiang Qian, Shifeng Wang, Xiaotian Yu, Zhi-Ming |
| author_facet | Wang, Jianhua Wang, Yang Zhou, Feng Wang, Wenhong Cheng, Zhenxiang Qian, Shifeng Wang, Xiaotian Yu, Zhi-Ming |
| contents | A pair of Weyl points (WPs) with opposite Chern numbers ${\cal{C}}$ can exhibit an additional higher-order $Z_2$ topological charge, giving rise to the formation of a $Z_2$ Weyl dipole. Owing to the nontrivial topological charge, $Z_2$ Weyl dipoles should also appear in pairs, and the WPs within each $Z_2$ Weyl dipole can not be annihilated when meeting together. As a novel topological state, the topological Weyl-dipole phase (TWDP) has garnered significant attention, yet its realization in crystalline materials remains a challenge. Here, through first-principles calculations and theoretical analysis, we demonstrate the existence of the Weyl-dipole phase in the phonon spectra of the $P6_3$ type Y(OH)$_3$. Particularly, the Weyl dipole in this system is protected by a quantized quadrupole moment, and it distinguished from conventional Weyl dipole, as it comprises an unconventional charge-3 WP with ${\cal{C}}=-3$ and three conventional charge-1 WPs with ${\cal{C}}=1$. Consequently, the Weyl-dipole phase in Y(OH)$_3$ features unique two-dimensional (2D) sextuple-helicoid Fermi-arc states on the top and bottom surfaces, protected by the Chern number, as well as one-dimensional (1D) hinge states that connect the two Weyl dipoles along the side hinges, guaranteed by the quantized quadrupole moment. Our findings not only introduce a novel higher-order topological phase, but also promote Y(OH)$_3$ as a promising platform for exploring multi-dimensional boundaries and the interaction between first-order and second-order topologies. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_16958 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Unconventional topological Weyl-dipole phonon Wang, Jianhua Wang, Yang Zhou, Feng Wang, Wenhong Cheng, Zhenxiang Qian, Shifeng Wang, Xiaotian Yu, Zhi-Ming Materials Science A pair of Weyl points (WPs) with opposite Chern numbers ${\cal{C}}$ can exhibit an additional higher-order $Z_2$ topological charge, giving rise to the formation of a $Z_2$ Weyl dipole. Owing to the nontrivial topological charge, $Z_2$ Weyl dipoles should also appear in pairs, and the WPs within each $Z_2$ Weyl dipole can not be annihilated when meeting together. As a novel topological state, the topological Weyl-dipole phase (TWDP) has garnered significant attention, yet its realization in crystalline materials remains a challenge. Here, through first-principles calculations and theoretical analysis, we demonstrate the existence of the Weyl-dipole phase in the phonon spectra of the $P6_3$ type Y(OH)$_3$. Particularly, the Weyl dipole in this system is protected by a quantized quadrupole moment, and it distinguished from conventional Weyl dipole, as it comprises an unconventional charge-3 WP with ${\cal{C}}=-3$ and three conventional charge-1 WPs with ${\cal{C}}=1$. Consequently, the Weyl-dipole phase in Y(OH)$_3$ features unique two-dimensional (2D) sextuple-helicoid Fermi-arc states on the top and bottom surfaces, protected by the Chern number, as well as one-dimensional (1D) hinge states that connect the two Weyl dipoles along the side hinges, guaranteed by the quantized quadrupole moment. Our findings not only introduce a novel higher-order topological phase, but also promote Y(OH)$_3$ as a promising platform for exploring multi-dimensional boundaries and the interaction between first-order and second-order topologies. |
| title | Unconventional topological Weyl-dipole phonon |
| topic | Materials Science |
| url | https://arxiv.org/abs/2502.16958 |