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

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.

References in corpus (4)

• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Titanic Magnetoresistance in WTe2
• Observation of the Quantum Spin Hall Effect up to 100 Kelvin in a Monolayer Crystal
• Nonsaturating magnetoresistance and nontrivial band topology of type-II Weyl semimetal NbIrTe4