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arXiv · 2105.07431

Layered van der Waals topological metals of TaTMTe4 (TM = Ir, Rh, Ru) family

G. Shipunov·B. R. Piening·C. Wuttke·T. A. Romanova·A. V. Sadakov·O. A. Sobolevskiy·E. Yu. Guzovsky·A. S. Usoltsev·V. M. Pudalov·D. Efremov·S. Subakti·D. Wolf·A. Lubk·B. Büchner·S. Aswartham
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Abstract

Layered van~der~Waals materials of the family TaTMTe$_4$ (TM=Ir, Rh, Ru) are showing very interesting electronic properties. Here we report the synthesis, crystal growth and structural characterization of TaIrTe$_4$, TaRhTe$_4$, TaIr$_{1-x}$Rh$_{x}$Te$_4$ ($x = 0.06$; 0.14; 0.78; 0.92) and Ta$_{1+x}$Ru$_{1-x}$Te$_4$ single crystals. For Ta$_{1+x}$Ru$_{1-x}$Te$_4$ off-stoichiometry is shown. X-ray powder diffraction confirms that TaRhTe4 is isostructural to TaIrTe4. We show that all these compounds are metallic with diamagnetic behavior. Ta$_{1.26(2)}$Ru$_{0.75(2)}$Te$_{4.000(8)}$ exhibits an upturn in the resistivity at low temperatures which is strongly field dependent. Below $T \approx 4$K we observed signatures of the superconductivity in the TaIr$_{1-x}$Rh$_{x}$Te$_4$ compounds for $x = 0.92$. Magnetotransport measurements on all samples show weak magnetoresistance (MR) field dependence that is typically quadratic-in-field. However, for TaIr$_{1-x}$Rh$_{x}$Te$_4$ with $x\approx 0.78$, the MR has a linear term dominating in low fields that indicates the presence of Dirac cones in the vicinity of the Fermi energy. For TaRhTe$_4$ series the MR is almost isotropic. We have performed electronic structure calculations for isostructural TaIrTe$_4$ and TaRhTe$_4$ together with the projected total density of states. The main difference is appearance of the Rh-band close to the Fermi level.

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G. Shipunov, B. R. Piening, C. Wuttke, T. A. Romanova, A. V. Sadakov, O. A. Sobolevskiy, E. Yu. Guzovsky, A. S. Usoltsev, V. M. Pudalov, D. Efremov, S. Subakti, D. Wolf, A. Lubk, B. Büchner, S. Aswartham. 2021-05-16. Layered van der Waals topological metals of TaTMTe4 (TM = Ir, Rh, Ru) family. https://doi.org/10.1021/acs.jpclett.1c01648

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