Raman Signatures of Broken Inversion Symmetry and In‐Plane Anisotropy in Type‐II Weyl Semimetal Candidate TaIrTe4 |
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| Authors: | Yinan Liu Qiangqiang Gu Yu Peng Shaomian Qi Na Zhang Yinong Zhang Xiumei Ma Rui Zhu Lianming Tong Ji Feng Zheng Liu Jian‐Hao Chen |
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| Affiliation: | 1. International Center for Quantum Materials, School of Physics, Peking University, Beijing, China;2. Centre for Programmed Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore;3. College of Chemistry and Molecular Engineering, Peking University, Beijing, China;4. Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China;5. CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China;6. Collaborative Innovation Center of Quantum Matter, Beijing, China;7. NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore |
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| Abstract: | The layered ternary compound TaIrTe4 is an important candidate to host the recently predicted type‐II Weyl fermions. However, a direct and definitive proof of the absence of inversion symmetry in this material, a prerequisite for the existence of Weyl Fermions, has so far remained evasive. Herein, an unambiguous identification of the broken inversion symmetry in TaIrTe4 is established using angle‐resolved polarized Raman spectroscopy. Combining with high‐resolution transmission electron microscopy, an efficient and nondestructive recipe to determine the exact crystallographic orientation of TaIrTe4 crystals is demonstrated. Such technique could be extended to the fast identification and characterization of other type‐II Weyl fermions candidates. A surprisingly strong in‐plane electrical anisotropy in TaIrTe4 thin flakes is also revealed, up to 200% at 10 K, which is the strongest known electrical anisotropy for materials with comparable carrier density, notably in such good metals as copper and silver. |
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| Keywords: | 2D material DFT calculations in‐plane anisotropy Raman spectroscopy type‐II Weyl semimetal |
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