Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi
© 2020 American Physical Society. Topological Weyl semimetal (WSM) is a solid-state realization of chiral Weyl fermions, whose phonon behaviors provide in-depth knowledge of their electronic properties. In this work, anisotropic Fano resonance is observed in a type-II WSM candidate LaAlSi by polariz...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society (APS)
2021
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| Online Access: | https://hdl.handle.net/1721.1/133321 |
| _version_ | 1811097425495982080 |
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| author | Zhang, Kunyan Wang, Tong Pang, Xiaoqi Han, Fei Shang, Shun-Li Hung, Nguyen T Liu, Zi-Kui Li, Mingda Saito, Riichiro Huang, Shengxi |
| author2 | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Zhang, Kunyan Wang, Tong Pang, Xiaoqi Han, Fei Shang, Shun-Li Hung, Nguyen T Liu, Zi-Kui Li, Mingda Saito, Riichiro Huang, Shengxi |
| author_sort | Zhang, Kunyan |
| collection | MIT |
| description | © 2020 American Physical Society. Topological Weyl semimetal (WSM) is a solid-state realization of chiral Weyl fermions, whose phonon behaviors provide in-depth knowledge of their electronic properties. In this work, anisotropic Fano resonance is observed in a type-II WSM candidate LaAlSi by polarized Raman spectroscopy. The asymmetric line shape occurs for the B12 phonon mode of LaAlSi only for 488- and 532-nm laser excitations but not for 364-, 633-, and 785-nm excitations, suggesting the excitation selectivity. The asymmetry, frequency, and linewidth of the B12 phonon mode, along with the spectral background, all show fourfold rotational symmetry as a function of the polarization angle in the polarized Raman spectra. While the shift of Raman frequency in a metal or semimetal is typically attributed to Kohn anomaly, here we show that the anisotropic frequency shift in LaAlSi cannot be explained by the effect of Kohn anomaly, but potentially by the anisotropic scattering background of Fano resonance. Origins of the excitation-energy dependence and anisotropic behavior of the Fano resonance are discussed by the first-principles calculated electronic band structure and phonon dispersion. |
| first_indexed | 2024-09-23T16:59:20Z |
| format | Article |
| id | mit-1721.1/133321 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T16:59:20Z |
| publishDate | 2021 |
| publisher | American Physical Society (APS) |
| record_format | dspace |
| spelling | mit-1721.1/1333212023-03-24T17:35:30Z Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi Zhang, Kunyan Wang, Tong Pang, Xiaoqi Han, Fei Shang, Shun-Li Hung, Nguyen T Liu, Zi-Kui Li, Mingda Saito, Riichiro Huang, Shengxi Massachusetts Institute of Technology. Department of Nuclear Science and Engineering © 2020 American Physical Society. Topological Weyl semimetal (WSM) is a solid-state realization of chiral Weyl fermions, whose phonon behaviors provide in-depth knowledge of their electronic properties. In this work, anisotropic Fano resonance is observed in a type-II WSM candidate LaAlSi by polarized Raman spectroscopy. The asymmetric line shape occurs for the B12 phonon mode of LaAlSi only for 488- and 532-nm laser excitations but not for 364-, 633-, and 785-nm excitations, suggesting the excitation selectivity. The asymmetry, frequency, and linewidth of the B12 phonon mode, along with the spectral background, all show fourfold rotational symmetry as a function of the polarization angle in the polarized Raman spectra. While the shift of Raman frequency in a metal or semimetal is typically attributed to Kohn anomaly, here we show that the anisotropic frequency shift in LaAlSi cannot be explained by the effect of Kohn anomaly, but potentially by the anisotropic scattering background of Fano resonance. Origins of the excitation-energy dependence and anisotropic behavior of the Fano resonance are discussed by the first-principles calculated electronic band structure and phonon dispersion. 2021-10-27T19:52:07Z 2021-10-27T19:52:07Z 2020 2021-08-11T16:53:51Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/133321 en 10.1103/PHYSREVB.102.235162 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society (APS) APS |
| spellingShingle | Zhang, Kunyan Wang, Tong Pang, Xiaoqi Han, Fei Shang, Shun-Li Hung, Nguyen T Liu, Zi-Kui Li, Mingda Saito, Riichiro Huang, Shengxi Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi |
| title | Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi |
| title_full | Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi |
| title_fullStr | Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi |
| title_full_unstemmed | Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi |
| title_short | Anisotropic Fano resonance in the Weyl semimetal candidate LaAlSi |
| title_sort | anisotropic fano resonance in the weyl semimetal candidate laalsi |
| url | https://hdl.handle.net/1721.1/133321 |
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