Superconducting dome associated with the suppression and re-emergence of charge density wave states upon sulfur substitution in CuIr2Te4 chalcogenides

TL;DR

This study explores how sulfur substitution in CuIr2Te4 affects charge density waves, superconductivity, and metal-insulator transitions, revealing a complex phase diagram with a superconducting dome linked to CDW suppression and re-emergence.

Contribution

It provides the first detailed phase diagram of CuIr2Te4-xSx, showing the interplay between CDW, superconductivity, and MIT with sulfur doping.

Findings

Suppression and re-emergence of CDW with S doping

Maximum Tc of 2.82 K at x=0.15

Observation of metal-insulator transition in the spinel region

Abstract

We report the path from the charge density wave (CDW)-bearing superconductor CuIr2Te4 to the metal insulator transition (MIT)-bearing compound CuIr2S4 by chemical alloying with the gradual substitution of S for Te. The evolution of structural and physical properties of the CuIr2Te4-xSx polycrystalline system with the doping range from 0 to 4 is systemically examined. The X-ray diffraction (XRD) results imply CuIr2Te4-xSx in the range between 0 and 0.5 crystallizes in a NiAs defected trigonal structure, whereas it adapts to the cubic spinel structure in the doping range from 3.6 to 4 and it is a mixed phase in the doping range from 0.5 to 3.6. Unexpectedly, the resistivity and magnetization measurements reveal that small-concentration S substitution for Te can suppress the CDW transition, but it reappears around x = 0.2, and the CDW transition temperature enhances clearly as x augments in the range from 0.2 to 0.5. Besides, the superconducting critical temperature (Tc) first increases with S doping content and then decreases after reaching a maximum Tc = 2.82 K for CuIr2Te3.85S0.15. MIT order has been observed in the spinel region from 3.6 to 4 associated with TMI increasing with x increasing. Finally, the rich electronic phase diagram of temperature versus x for this CuIr2Te4-xSx system is assembled, where the superconducting dome is associated with the suppression and re-emergence of CDW as well as MIT states at the end upon sulfur substitution in the CuIr2Te4-xSx chalcogenides.