Université de Fribourg

Optical conductivity of the type-II Weyl semimetal TaIrTe4

Mardelé, F. Le ; Santos-Cottin, D. ; Martino, E. ; Semeniuk, K. ; David, S. Ben ; Orbanić, F. ; Novak, Mark ; Rukelj, Z. ; Homes, C. C. ; Akrap, Ana

In: Physical Review B, 2020, vol. 102, no. 4, p. 045201

TaIrTe4 is 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 toWeyl 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...

Université de Fribourg

Probing intraband excitations in ${\mathrm{ZrTe}}_{5}$: A high-pressure infrared and transport study

Santos-Cottin, D. ; Padlewski, M. ; Martino, E. ; David, S. Ben ; Mardelé, F. Le ; Capitani, F. ; Borondics, F. ; Bachmann, M. D. ; Putzke, C. ; Moll, P. J. W. ; Zhong, R. D. ; Gu, G. D. ; Berger, H. ; Orlita, M. ; Homes, C. C. ; Rukelj, Z. ; Akrap, Ana

In: Physical Review B, 2020, vol. 101, no. 12, p. 125205

Zirconium pentatetelluride, ZrTe5, shows remarkable sensitivity to hydrostatic pressure. In this work we address the high-pressure transport and optical properties of this compound, on samples grown by flux and chemical vapor transport. The high-pressure resistivity is measured up to 2 GPa, and the infrared transmission up to 9 GPa. The dc conductivity anisotropy is determined using a...

Université de Fribourg

Linear behavior of the optical conductivity and incoherent charge transport in ${\mathrm{BaCoS}}_{2}$

Santos-Cottin, D. ; Klein, Y. ; Werner, Philipp ; Miyake, Takashi ; Medici, L. de ; Gauzzi, A. ; Lobo, R. P. S. M. ; Casula, Michele

In: Physical Review Materials, 2018, vol. 2, no. 10, p. 105001

Optical conductivity measurements on a BaCoS2 single crystal unveil an unusual linear behavior over a broad spectral range. In the paramagnetic phase above 300 K, the spectrum shows no gap, which contradicts the previously proposed scenario of a charge-transfer Mott insulator. Ab initio dynamical mean field theory calculations including a retarded Hubbard interaction explain the data in terms...