Anisotropic intermediate coupling superconductivity in Cu0.03TaS2

The anisotropic superconducting state properties in Cu0.03TaS2 have been investigated by magnetization, magnetoresistance and specific heat measurements. They clearly show that Cu0.03TaS2 undergoes a superconducting transition at TC = 4.03 K. The obtained superconducting parameters demonstrate that Cu0.03TaS2 is an anisotropic type-II superconductor. Combining specific heat jump DeltaC/gammanTC = 1.6(4), gap ratio 2Delta/kBTC = 4.0(9) and the estimated electron-phonon coupling constant lambda~0.68, the superconductivity in Cu0.03TaS2 is explained within the intermediate coupling BCS scenario. First-principles electronic structure calculations suggest that copper intercalation of 2H-TaS2 causes a considerable increase of the Fermi surface volume and the carrier density, which suppresses the CDW fluctuation and favors the raise of TC.