We report a systematic investigation on the evolution of the structural and physical properties, including the charge density wave (CDW) and superconductivity of the polycrystalline CuIr2Te4−x I x for 0.0 ≤ x ≤ 1.0. X-ray diffraction results indicate that both of a and c lattice parameters increase linearly when 0.0 ≤ x ≤ 1.0. The resistivity measurements indicate that the CDW is destabilized with slight x but reappears at x ≥ 0.9 with very high T CDW. Meanwhile, the superconducting transition temperature T c enhances as x increases and reaches a maximum value of around 2.95 K for the optimal composition CuIr2Te1.9I0.1 followed by a slight decrease with higher iodine doping content. The specific heat jump (ΔC/γT c) for the optimal composition CuIr2Te3.9I0.1 is approximately 1.46, which is close to the Bardeen–Cooper–Schrieffer value of 1.43, indicating that it is a bulk superconductor. The results of thermodynamic heat capacity measurements under different magnetic fields [C p(T, H)], magnetization M(T, H) and magneto-transport ρ(T, H) measurements further suggest that CuIr2Te4−x I x bulks are type-II superconductors. Finally, an electronic phase diagram for this CuIr2Te4−x I x system has been constructed. The present study provides a suitable material platform for further investigation of the interplay of the CDW and superconductivity.

We report the crystal structure, charge-density-wave (CDW), superconductivity (SC), and ferromagnetism (FM) in CuIr2-xCrxTe4 (0 ≤ x ≤ 2) chalcogenides. Powder x-ray diffraction (PXRD) results reveal that CuIr2-xCrxTe4 series are distinguished between two structural types and three different regions: (i) layered trigonal structure region, (ii) mixed phase regions, (iii) spinel structure region. Besides, Cr substitution for Ir site results in rich physical properties including the collapse of CDW, the formation of dome-shaped like SC, and the emergence of magnetism. Cr doping slightly elevates the superconducting critical temperature (Tsc) to its highest Tsc = 2.9 K around x = 0.06. As x increases from 0.3 to 0.4, the ferromagnetic Curie temperature (Tc) increases from 175 to 260 K. However, the Tc remains unchanged in the spinel range of 1.9 ≤ x ≤ 2. This finding provides a comprehensive material platform for investigating the interplay between CDW, SC, and FM multipartite quantum states.

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We report the anomalous charge density wave (CDW) state evolution and dome-like superconductivity in CuIr2Te4−x Se x (0 ⩽ x ⩽ 0.5) series. Room temperature powder x-ray diffraction (XRD) results indicate that CuIr2Te4−x Se x (0 ⩽ x ⩽ 0.5) compounds retain the same structure as the host CuIr2Te4 and the unit cell constants a and c manifest a linear decline with increasing Se content. Magnetization, resistivity and heat capacity results suggest that superconducting transition temperature (T c) exhibits a weak dome-like variation as substituting Te by Se with the maximum T c = 2.83 K for x = 0.1 followed by suppression in T c and simultaneous decrease of the superconducting volume fraction. Unexpectedly, the CDW-like transition (T CDW) is suppressed with lower Se doping (0.025 ⩽ x ⩽ 0.2) but re-emerges at higher doping (0.25 ⩽ x ⩽ 0.5). Meanwhile, the temperature-dependent XRD measurements show that the trigonal structure is stable at 20 K, 100 K and 300 K for the host sample and the doping composition with x = 0.5, thus we propose that the behavior CDW-like transition arises from the disorder effect created by chemical doping and is not related to structural transition. The lower and the upper critical fields of these compounds are also addressed.

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