Optical conductivity of the type-II Weyl semimetal TaIrTe4

• Published in: Physical review. B 2020-07, Vol.102 (4), p.1
• Main Authors: Le Mardelé, F, Santos-Cottin, D, Martino, E, Semeniuk, K, David, S Ben, Orbanić, F, Novak, M, Rukelj, Z, Homes, C C, Akrap, Ana
• Format: Article
• Language: English
• Subjects: Band structure of solids; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Conductivity; Dispersion; Nodes
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.102.045201

TaIrTe4is an example of a candidate Weyl type-II semimetal with a minimal possible number of Weyl nodes. Four nodes are reported to exist in 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 TaIrTe4, 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 × 104 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 TaIrTe4.