Superconductivity in the Ru-Doped CuIr2Te4 Telluride Chalcogenide

TL;DR

This study investigates how Ru doping affects the structural and superconducting properties of CuIr2Te4 telluride, revealing optimal doping levels, strong electron-phonon coupling, and a competition between charge density wave and superconductivity.

Contribution

It provides the first systematic analysis of Ru doping effects on CuIr2Te4, identifying optimal doping for superconductivity and elucidating the interplay between CDW and superconductivity.

Findings

Optimal Tc of 2.79 K at x=0.05 Ru doping

Superconductivity is strongly electron-phonon coupled

Charge density wave disappears at x=0.03

Abstract

Here we report the effect of structural and superconductivity properties on Ru doped CuIr2Te4 telluride chalcogenide. XRD results suggest that the CuIr2-xRuxTe4 maintain the disordered trigonal structure with space group P3m1 (No. 164) for x less than 0.3. The lattice constants, a and c, both decrease with increasing Ru content. Temperature-dependent resistivity, magnetic susceptibility and specific-heat measurements are performed to characterize the superconducting properties systematically. Our results suggest that the optimal doping level for superconductivity in CuIr2-xRuxTe4 is x = 0.05, where Tc is 2.79 K with the Sommerfeld constant gamma of 11.52 mJ mol-1 K-2 and the specific-heat anomaly at the superconducting transition, is approximately 1.51, which is higher than the BCS value of 1.43, indicating CuIr1.95Ru0.05Te4 is a strongly electron-phonon coupled superconductor. The values of lower critical filed and upper critical field calculated from isothermal magnetization and magneto-transport measurements are 0.98 KOe and 2.47 KOe respectively, signifying that the compound is clearly a type-II superconductor. Finally, a dome-like shape superconducting Tcs vs. x content phase diagram is established, where the charge density wave disappears at x = 0.03 while superconducting transition temperature (Tc) rises until it reaches its peak at x = 0.05, then, with decreasing when x reaches 0.3. This feature of the competition between CDW and the superconductivity could be caused by tuning the Fermi surface and density of states with Ru chemical doping.