Superconductivity and Charge Density Wave of CuIr2Te4 by Iodine Doping

TL;DR

This study explores how iodine doping affects the structural, charge density wave, and superconducting properties of CuIr2Te4, revealing a tunable phase diagram with optimal superconductivity at specific doping levels.

Contribution

It provides the first systematic investigation of iodine doping effects on CuIr2Te4, demonstrating the enhancement of superconductivity and the interplay with charge density wave phenomena.

Findings

Superconducting transition temperature reaches 2.95 K at optimal doping.

Charge density wave is suppressed and reappears with varying iodine content.

CuIr2Te4-xIx is confirmed as a type II superconductor.

Abstract

Here we report a systematic investigation on the evolution of the structural and physical properties, including the charge density wave and superconductivity of the polycrystalline CuIr2Te4-xIx. X-ray diffraction results indicate that both of a and c lattice parameters increase linearly. The resistivity measurements indicate that the charge density wave is destabilized with slight x but reappears when x is large than 0.9. Meanwhile, the superconducting transition temperature enhances as x raises and reaches a maximum value of around 2.95 K for the optimal composition CuIr2Te3.9I0.1 followed by a slight decrease with higher iodine doping content. The specific heat jump for the optimal composition CuIr2Te3.9I0.1 is approximately 1.46, which is close to the Bardeen Cooper Schrieffer value which is 1.43, indicating it is a bulk superconductor. The results of thermodynamic heat capacity measurements under different magnetic fields, magnetization and magneto-transport measurements further suggest that CuIr2Te4-xIx bulks are type II superconductors. Finally, an electronic phase diagram for this CuIr2Te4-xIx system has been constructed. The present study provides a suitable material platform for further investigation of the interplay of the CDW and superconductivity.