Tuning the Charge Density Wave and Superconductivity in Cux TaS2
We report the characterization of layered 2H -type Cux TaS2 for 0≤x≤0.12. The charge density wave (CDW), at 70 K for TaS2, is destabilized with Cu doping. The sub-1 K superconducting transition in undoped 2H -TaS2 jumps quickly to 2.5 K at low x, increases to 4.5 K at the optimal composition Cu0.04 TaS2, and then decreases at higher x. The electronic contribution to the specific heat, first increasing and then decreasing as a function of Cu content, is 12 mJ mol-1 K-2 at Cu0.04 TaS2. Electron-diffraction studies show that the CDW remains present at the optimal superconducting composition but with both a changed q vector and decreased coherence length. We present an electronic phase diagram for the system.
K. E. Wagner and E. Morosan and Y. S. Hor and J. Tao and Y. Zhu and T. Sanders and T. M. McQueen and H. W. Zandbergen and A. J. Williams and D. V. West and R. J. Cava, "Tuning the Charge Density Wave and Superconductivity in Cux TaS2," Physical Review B - Condensed Matter and Materials Physics, vol. 78, no. 10, American Physical Society (APS), Sep 2008.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.78.104520
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