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arXiv · 2004.00147

Optical conductivity of the type-II Weyl semimetal TaIrTe$_4$

F. Le Mardelé·D. Santos-Cottin·E. Martino·K. Semeniuk·S. Ben David·F. Orbanic·M. Novak·Z. Rukelj·C. C. Homes·Ana Akrap
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Abstract

TaIrTe$_4$ is an example of a candidate Weyl type-II semimetal with a minimal possible number of Weyl nodes. Four nodes are reported to exist a single plane in $k$-space. The existence of a conical dispersion linked to Weyl nodes has yet to be shown experimentally. Here we use optical spectroscopy as a probe of the band structure on a low-energy scale. Studying optical conductivity allows us to probe intraband and interband transitions with zero momentum. In TaIrTe$_4$, we observe a narrow Drude contribution and an interband conductivity that may be consistent with a tilted linear band dispersion up to 40~meV. The interband conductivity allows us to establish the effective parameters of the conical dispersion; effective velocity $v=1.1\cdot 10^{4}$~m/s and tilt $\gamma=0.37$. The transport data, Seebeck and Hall coefficients, are qualitatively consistent with conical features in the band structure. Quantitative disagreement may be linked to the multiband nature of TaIrTe$_4$.

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F. Le Mardelé, D. Santos-Cottin, E. Martino, K. Semeniuk, S. Ben David, F. Orbanic, M. Novak, Z. Rukelj, C. C. Homes, Ana Akrap. 2020-03-31. Optical conductivity of the type-II Weyl semimetal TaIrTe$_4$. https://doi.org/10.1103/physrevb.102.045201

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