Dual dome-like Superconductivity in CuIr2Te3.85S0.15-xSex Chalcogenides

In this paper, we report the superconductivity (SC) evolution on Se-substitution CuIr2Te3.85S0.15 telluride chalcogenide. The results of powder X ray-diffraction (PXRD) show that CuIr2Te3.85S0.15Se0.15-x (0≤x≤0.15) series maintain a layered triangular structure and the space group are P3-m1 (No.164). Both the lattice constants a and c increase with increasing Se content. To systematically characterize the superconductivity properties, the electrical, magnetic, and thermal properties of the CuIr2Te3.85S0.15Se0.15-x (0≤x≤0.15) series were tested. The resistivity and magnetic susceptibility measurements reveal that when Se gradually replaces S, CuIr2Te3.85S0.15Se0.15-x remains superconducting at low temperatures and does not disappear or transform into other electron ground states. In addition, With the increase of Se doping, the superconducting critical temperature (Tc) Rises and then falls twice, so the Tc value has two peaks in CuIr2Te3.85S0.15Se0.15-x (0≤x≤0.15) series. Finally, we plot a phase plot of the superconducting transition temperature (Tc) versus the x content, which shows a "double dome" shape. CuIr2Te3.85S0.15Se0.15-x retains the inhibitory effect on CDW as the host CuIr2Te3.85S0.15. This peculiar change in superconducting transition temperature may be due to the change in the density of states at the Fermi surface caused by Se doping.