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| Format: | Preprint |
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2024
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| Online-Zugang: | https://arxiv.org/abs/2405.14165 |
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| _version_ | 1866918269996236800 |
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| author | He, Qinghua Zhang, Jie Tao, Shengdan Deng, Hai-yao Liang, Qifeng Gao, Wenlong Liu, Feng |
| author_facet | He, Qinghua Zhang, Jie Tao, Shengdan Deng, Hai-yao Liang, Qifeng Gao, Wenlong Liu, Feng |
| contents | Nonsymmorphic symmetries can enforce band connectivity that obstructs a single-band Wannier description. We show that a fractional translation $\mathcal{L}$ connecting distinct high-symmetry Wyckoff positions generically renders the Wannier center of an individual band gauge ill-defined, requiring a symmetry-enforced multiband object -- a Wannier complex. We formulate a real-space topological classification of Wannier complexes and show that, when $\mathcal{L}$ is combined with certain point-group symmetries (notably $C_4$ and $C_3$), all symmetry-allowed Wannier-complex configurations carry a nontrivial quantized total electric polarization. This yields boundary phenomena that persist across symmetry-preserving deformations of the Hamiltonian, including parameter regimes with and without bulk gaps. We demonstrate the mechanism in minimal tight-binding models exhibiting M{ö}bius-twisted Wilson-loop structures and higher-order corner modes, and propose experimental signatures in a dielectric photonic crystal and a first-principles electronic platform octa-graphene, accompanied by a three-dimensional extension. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2405_14165 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Band-Structure-Independent Topology from Nonsymmorphic Wannier Complexes He, Qinghua Zhang, Jie Tao, Shengdan Deng, Hai-yao Liang, Qifeng Gao, Wenlong Liu, Feng Superconductivity Nonsymmorphic symmetries can enforce band connectivity that obstructs a single-band Wannier description. We show that a fractional translation $\mathcal{L}$ connecting distinct high-symmetry Wyckoff positions generically renders the Wannier center of an individual band gauge ill-defined, requiring a symmetry-enforced multiband object -- a Wannier complex. We formulate a real-space topological classification of Wannier complexes and show that, when $\mathcal{L}$ is combined with certain point-group symmetries (notably $C_4$ and $C_3$), all symmetry-allowed Wannier-complex configurations carry a nontrivial quantized total electric polarization. This yields boundary phenomena that persist across symmetry-preserving deformations of the Hamiltonian, including parameter regimes with and without bulk gaps. We demonstrate the mechanism in minimal tight-binding models exhibiting M{ö}bius-twisted Wilson-loop structures and higher-order corner modes, and propose experimental signatures in a dielectric photonic crystal and a first-principles electronic platform octa-graphene, accompanied by a three-dimensional extension. |
| title | Band-Structure-Independent Topology from Nonsymmorphic Wannier Complexes |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2405.14165 |