Observation of a Charge Density Wave Incommensuration Near the Superconducting Dome in CuxTiSe2

TL;DR

This study uses X-ray diffraction to explore how charge density waves evolve with copper doping in CuxTiSe2, revealing incommensuration near the superconducting dome and suggesting a link between CDW incommensuration and superconductivity.

Contribution

It provides new insights into the persistence and incommensuration of charge density waves across a wider doping range than previously known, highlighting their potential role in superconductivity.

Findings

CDW incommensuration appears at x≈0.055, coinciding with superconductivity onset

Charge density waves persist up to x≈0.091, beyond previous assumptions

CDW does not terminate within the superconducting dome

Abstract

X-ray diffraction was employed to study the evolution of the charge density wave (CDW) in CuxTiSe2 as a function of copper intercalation in order to clarify the relationship between the CDW and superconductivity. The results show a CDW incommensuration arising at an intercalation value coincident with the onset of superconductivity at around x=0.055(5). Additionally, it was found that the charge density wave persists to higher intercalant concentrations than previously assumed, demonstrating that the CDW does not terminate inside the superconducting dome. A charge density wave peak was observed in samples up to x=0.091(6), the highest copper concentration examined in this study. The phase diagram established in this work suggests that charge density wave incommensuration may play a role in the formation of the superconducting state.