Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄
Rotational-symmetry-protected topological crystalline insulators (TCIs) are expected to host unique boundary modes, in that the surface normal to the rotational axis can feature surface states with 'unpinned' Dirac points, which are not constrained to lie on high symmetry points or lines,...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2020
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| Online Access: | https://hdl.handle.net/1721.1/128695 |
| _version_ | 1811076065911635968 |
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| author | Ma, Qiong Gedik, Nuh Fu, Liang Xu, Suyang |
| author2 | MIT Materials Research Laboratory |
| author_facet | MIT Materials Research Laboratory Ma, Qiong Gedik, Nuh Fu, Liang Xu, Suyang |
| author_sort | Ma, Qiong |
| collection | MIT |
| description | Rotational-symmetry-protected topological crystalline insulators (TCIs) are expected to host unique boundary modes, in that the surface normal to the rotational axis can feature surface states with 'unpinned' Dirac points, which are not constrained to lie on high symmetry points or lines, but can lie at any general k point in the Brillouin zone. Also, as a higher order bulk boundary correspondence is involved here, a three-dimensional (3D) TCI can support one-dimensional (1D) helical edge states. Using first-principles band structure calculations, we identify the van der Waals material-Bi4Br4 as a purely rotation symmetry protected TCI. We show that the surface of Bi4Br4 exhibits a pair of unpinned topological Dirac fermions which are related to the presence of a two-fold rotation axis. These unpinned Dirac fermions possess an exotic spin texture which will be highly favorable for spin transport, and a band structure that consists of van Hove singularities due to a Lifshitz transition. We also identify 1D topological hinge states along the edges of an-Bi4Br4 rod. We comment on how the predicted topological features in-Bi4Br4 could be accessed experimentally. |
| first_indexed | 2024-09-23T10:15:33Z |
| format | Article |
| id | mit-1721.1/128695 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T10:15:33Z |
| publishDate | 2020 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1286952022-09-30T19:58:40Z Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ Ma, Qiong Gedik, Nuh Fu, Liang Xu, Suyang MIT Materials Research Laboratory Massachusetts Institute of Technology. Department of Physics Rotational-symmetry-protected topological crystalline insulators (TCIs) are expected to host unique boundary modes, in that the surface normal to the rotational axis can feature surface states with 'unpinned' Dirac points, which are not constrained to lie on high symmetry points or lines, but can lie at any general k point in the Brillouin zone. Also, as a higher order bulk boundary correspondence is involved here, a three-dimensional (3D) TCI can support one-dimensional (1D) helical edge states. Using first-principles band structure calculations, we identify the van der Waals material-Bi4Br4 as a purely rotation symmetry protected TCI. We show that the surface of Bi4Br4 exhibits a pair of unpinned topological Dirac fermions which are related to the presence of a two-fold rotation axis. These unpinned Dirac fermions possess an exotic spin texture which will be highly favorable for spin transport, and a band structure that consists of van Hove singularities due to a Lifshitz transition. We also identify 1D topological hinge states along the edges of an-Bi4Br4 rod. We comment on how the predicted topological features in-Bi4Br4 could be accessed experimentally. United States. Department of Energy. Office of Basic Energy Science (Grant DE-FG02-07ER46352) United States. Department of Energy (Grant DE-AC02-05CH11231) United States. Department of Energy. Division of Materials Sciences and Engineering (Award DE-SC0018945) National Science Foundation (U.S.) (Grant DMR-1231319) 2020-11-30T20:06:57Z 2020-11-30T20:06:57Z 2019-05 2019-03 2020-10-23T16:49:07Z Article http://purl.org/eprint/type/JournalArticle 2053-1583 https://hdl.handle.net/1721.1/128695 Hsu, Chuang-Han et al. “Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄.” 2D Materials, 6, 3 (May 2019): 031004 © 2019 The Author(s) en 10.1088/2053-1583/AB1607 2D Materials Creative Commons Attribution 3.0 unported license https://creativecommons.org/licenses/by/3.0/ application/pdf IOP Publishing IOP Publishing |
| spellingShingle | Ma, Qiong Gedik, Nuh Fu, Liang Xu, Suyang Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ |
| title | Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ |
| title_full | Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ |
| title_fullStr | Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ |
| title_full_unstemmed | Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ |
| title_short | Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄ |
| title_sort | purely rotational symmetry protected topological crystalline insulator α bi₄ br₄ |
| url | https://hdl.handle.net/1721.1/128695 |
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