Effect of Ti substitution on the superconductivity of CuIr2Te4 telluride chalcogenide

Unconventional superconductivity often appears in proximity of symmetry-breaking electronic and magnetic orders. The relevance of spatiotemporal fluctuations of these orders for the superconducting pairing remains an open question. Here, nanoscale broken-symmetry states are probed by high-energy x-rays in a layered iridium ditelluride superconductor, where superconductivity emerges from an ordered dimer state. The study finds no fingerprints of dimer fluctuations in the superconducting compositional regime, yet provides evidence for the coexistence of superconductivity and nanoscale dimerization close to the phase boundary of these two electronic states.

Phase separation at the dimer-superconductor transition in Ir 1−x Rh x Te 2

We report the anomalous charge density wave (CDW) state evolution and dome-like superconductivity (SC) in CuIr2Te4-xSex series. Room temperature powder X ray-diffraction (PXRD) results indicate that CuIr2Te4-xSex 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 (Tc) exhibits a weak dome-like variation as substituting Te by Se with the maximum Tc = 2.83 K for x = 0.1 followed by suppression in Tc and simultaneous decrease of the superconducting volume fraction. Unexpectedly, the CDW-like transition (TCDW) is suppressed with lower Se doping but re-emerges at higher doping. 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 behaviour 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.

Anomalous Charge Density Wave State Evolution and Dome-like Superconductivity in CuIr2Te4-xSex Chalcogenides

Charge Density Wave and Electron-Phonon Interaction in Epitaxial Monolayer NbSe$_{2}$ Films

Lingyong Zeng, Yi Ji, Dongpeng Yu, Shu Guo, Yiyi He, Kuan Li, Yanhao Huang, Chao Zhang, Peifeng Yu, Shaojuan Luo, Huichao Wang, Huixia Luo School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Key Lab of Polymer Composite & Functional Materials, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-Sen University, No. 135, Xingang Xi Road, Guangzhou, 510275, P. R. China

/pdf/negative-chemical-pressure-effect-on-the-superconductivity-1tu7psdp.pdf

Negative Chemical Pressure Effect on the Superconductivity and Charge Density Wave of Cu0.5Ir1–xZrxTe2

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.

Wang Huichao

Papers

Superconductivity and Charge Density Wave in Iodine-Doped CuIr$_{2}$Te$_{4}$