Superconductivity in a low carrier density system: A single crystal study of cubic $Y3Ru4Ge13$

We have successfully grown the single crystal of $Y3Ru4Ge13$ which crystallizes in the cubic crystal structure with the space group Pm3n. $Y3Ru4Ge13$ exhibits superconductivity below 2.85K as determined using electrical resistivity, magnetic susceptibility and heat capacity measurements. Hall Effect measurements show that the Hall coefficient R_H is negative and its value decreases rapidly with temperature, which is highly unusual. The simple estimation of the carrier concentration gives a value ≅10²⁰/cm³, which are 2–3 orders of magnitude lower than that of a conventional metal like Cu, suggesting $Y3Ru4Ge13$ is a semimetal.