arXiv, 2020
DOI: 10.48550/arxiv.2004.00147
American Physical Society, Physical review B, 4(102), 2020
DOI: 10.1103/physrevb.102.045201
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 $v=1.1⋅ 10^{4}$~m/s and tilt $γ=0.37$. 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$_4$.