Superconductivity induced by La doping in Sr1−xLaxFBiS2

Through a combination of x-ray diffraction, electrical transport, magnetic susceptibility, and heat-capacity measurements, we report the effect of La doping on Sr in the newly discovered SrFBiS${}_{2}$ system. Superconducting transition with critical temperature T${}_{c}$ of 2.8 K, developed from a semiconducting-like normal state, was found in Sr${}_{0.5}$La${}_{0.5}$FBiS${}_{2}$. A strong diamagnetic signal and a clear specific-heat anomaly associated with this transition were observed, confirming bulk superconductivity. The upper critical field ${H}_{c2}(0)$ was estimated to be 1 T by using the Ginzburg-Landau approach. Our experiments therefore demonstrate that bulk superconductivity can be achieved by electron doping in the SrFBiS${}_{2}$ system.