Transport properties in Cu$_{x}$TiSe$_{2}$ (0.015$\leq$x$\leq$0.110) Single Crystal

TL;DR

This study systematically investigates the transport properties of Cu$_{x}$TiSe$_{2}$ single crystals, revealing the suppression of charge density waves, enhancement of superconductivity with Cu doping, and notable anisotropic and thermoelectric behaviors.

Contribution

It provides new insights into how Cu intercalation affects the charge density wave and superconductivity in TiSe$_{2}$, including detailed transport measurements and anisotropy analysis.

Findings

Charge density wave is suppressed around x=0.055.

Superconductivity is enhanced with Cu doping but not observed above 1.8 K at x=0.11.

Large thermopower and negative magnetoresistance are observed.

Abstract

Transport properties are systematically studied for the single crystals Cu$_{x}$TiSe$_{2}$ (0.015$\leq$x$\leq$0.110). Both of in-plane and out-of-plane resistivity show the coexistence of superconducting transition and charge density wave (CDW) for the single crystals with $x \leq 0.025$. After CDW state is completely suppressed around x=0.055, the superconductivity is apparently enhanced by Cu doping. No superconducting transition is observed above 1.8 K for Cu$_{0.11}$TiSe$_{2}$. Anisotropy in resistivity increases with increasing Cu content, and is nearly $T$-independent. CDW state has a strong effect on Hall coefficient and thermopower. A large thermopower, comparable to the triangle lattice $NaxCoO_2$, is observed in Cu$_{x}$TiSe$_{2}$. Intercalation of Cu induces a negative MR due to the interaction between conducting carries and localized magnetic moments.