Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP
Abstract Degenerate points/lines in the band structures of crystals have become a staple of the growing number of topological materials. The bulk-boundary correspondence provides a relation between bulk topology and surface states. While line degeneracies of bulk excitations have been extensively ch...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2021-12-01
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| Series: | npj Computational Materials |
| Online Access: | https://doi.org/10.1038/s41524-021-00667-6 |
| _version_ | 1828957785094619136 |
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| author | Bo Peng Shuichi Murakami Bartomeu Monserrat Tiantian Zhang |
| author_facet | Bo Peng Shuichi Murakami Bartomeu Monserrat Tiantian Zhang |
| author_sort | Bo Peng |
| collection | DOAJ |
| description | Abstract Degenerate points/lines in the band structures of crystals have become a staple of the growing number of topological materials. The bulk-boundary correspondence provides a relation between bulk topology and surface states. While line degeneracies of bulk excitations have been extensively characterised, line degeneracies of surface states are not well understood. We show that SnIP, a quasi-one-dimensional van der Waals material with a double helix crystal structure, exhibits topological nodal rings/lines in both the bulk phonon modes and their corresponding surface states. Using a combination of first-principles calculations, symmetry-based indicator theories and Zak phase analysis, we find that two neighbouring bulk nodal rings form doubly degenerate lines in their drumhead-like surface states, which are protected by the combination of time-reversal symmetry $${{{\mathcal{T}}}}$$ T and glide mirror symmetry $${\bar{M}}_{y}$$ M ¯ y . Our results indicate that surface degeneracies can be generically protected by symmetries such as $${{{\mathcal{T}}}}{\bar{M}}_{y}$$ T M ¯ y , and phonons provide an ideal platform to explore such degeneracies. |
| first_indexed | 2024-12-14T08:35:22Z |
| format | Article |
| id | doaj.art-67b0e4defc4041418ac0533f410c385d |
| institution | Directory Open Access Journal |
| issn | 2057-3960 |
| language | English |
| last_indexed | 2024-12-14T08:35:22Z |
| publishDate | 2021-12-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Computational Materials |
| spelling | doaj.art-67b0e4defc4041418ac0533f410c385d2022-12-21T23:09:25ZengNature Portfolionpj Computational Materials2057-39602021-12-01711810.1038/s41524-021-00667-6Degenerate topological line surface phonons in quasi-1D double helix crystal SnIPBo Peng0Shuichi Murakami1Bartomeu Monserrat2Tiantian Zhang3TCM Group, Cavendish Laboratory, University of CambridgeDepartment of Physics, Tokyo Institute of Technology, Ookayama, Meguro-kuTCM Group, Cavendish Laboratory, University of CambridgeDepartment of Physics, Tokyo Institute of Technology, Ookayama, Meguro-kuAbstract Degenerate points/lines in the band structures of crystals have become a staple of the growing number of topological materials. The bulk-boundary correspondence provides a relation between bulk topology and surface states. While line degeneracies of bulk excitations have been extensively characterised, line degeneracies of surface states are not well understood. We show that SnIP, a quasi-one-dimensional van der Waals material with a double helix crystal structure, exhibits topological nodal rings/lines in both the bulk phonon modes and their corresponding surface states. Using a combination of first-principles calculations, symmetry-based indicator theories and Zak phase analysis, we find that two neighbouring bulk nodal rings form doubly degenerate lines in their drumhead-like surface states, which are protected by the combination of time-reversal symmetry $${{{\mathcal{T}}}}$$ T and glide mirror symmetry $${\bar{M}}_{y}$$ M ¯ y . Our results indicate that surface degeneracies can be generically protected by symmetries such as $${{{\mathcal{T}}}}{\bar{M}}_{y}$$ T M ¯ y , and phonons provide an ideal platform to explore such degeneracies.https://doi.org/10.1038/s41524-021-00667-6 |
| spellingShingle | Bo Peng Shuichi Murakami Bartomeu Monserrat Tiantian Zhang Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP npj Computational Materials |
| title | Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP |
| title_full | Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP |
| title_fullStr | Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP |
| title_full_unstemmed | Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP |
| title_short | Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP |
| title_sort | degenerate topological line surface phonons in quasi 1d double helix crystal snip |
| url | https://doi.org/10.1038/s41524-021-00667-6 |
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