Transport properties in Cu${}_x$TiSe${}_2$ (0.015$\le$x$\le$0.110) Single Crystal

Abstract

Transport properties are systematically studied for the single crystals Cu${}_x$TiSe${}_2$ (0.015$\le$x$\le$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 $x\le 0.025$. 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 $NaxCo{O}_2$, 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.

6 pages, 6 figures