Optical conductivity of the type-II Weyl semimetal TaIrTe\(_4\)

• Published in: arXiv.org 2020-03
• Main Authors: F Le Mardelé, Santos-Cottin, D, Martino, E, Semeniuk, K, S Ben David, Orbanic, F, Novak, M, Rukelj, Z, Homes, C C, Akrap, Ana
• Format: Article
• Language: English
• Subjects: Band structure of solids; Conductivity; Dispersion; Nodes
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2004.00147

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\(_4\).