Anomalous phonon-mode dependence in polarized Raman spectroscopy of the topological Weyl semimetal TaP
Name
PhysRevB.101.014308.pdf
Size
2.2 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Zhang, Kunyan
Pang, Xiaoqi
Wang, Tong
Han, Fei
Shang, Shun-Li
Hung, Nguyen T.
Nugraha, Ahmad R. T.
Liu, Zi-Kui
Li, Mingda
Saito, Riichiro
Date Issued
January 2020
Journal
Physical Review B
Publisher
American Physical Society
Citation
Zhang, Kunyan, et al. "Anomalous phonon-mode dependence in polarized Raman spectroscopy of the topological Weyl semimetal TaP." Physical Review B, 101, 1 (January 2020): 014308. © 2020 American Physical Society
Version
Final published version
Abstract
Topological Weyl semimetals (WSMs) have attracted widespread interest due to the chiral Weyl fermions and surface Fermi arcs that enable unique optical and transport phenomena. In this work, we present angle-resolved Raman spectroscopy of TaP, a prototypical noncentrosymmetric WSM, for five excitation wavelengths ranging from 364 to 785 nm. The Raman-active modes, A_{1}, B_{1}^{1}, and B_{1}^{2} modes, exhibit two main unique features beyond the conventional Raman theory. First, the relative intensities of Raman-active modes change as a function of the excitation wavelength. Second, angle-resolved polarized Raman spectra show systematic deviation from the Raman tensor theory. In particular, the B_{1}^{1} mode is absent for 633-nm excitation, whereas the B_{1}^{2} mode shows an unusual twofold symmetry instead of a fourfold symmetry for 488-, 532-, and 633-nm excitations. These unconventional phenomena are attributed to the interference effect in the Raman process owing to the existence of multiple carrier pockets with almost the same energy but different symmetries.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.101.014308
