Two-Gap Superconductivity in Lu$_{2}$Fe$_{3}$Si$_{5}$

Lu$_{2}$Fe$_{3}$Si$_{5}$ is a superconductor with $T_{c}\sim $ 6 K containing nonmagnetic irons. Anomalous temperature dependence of specific heat in the superconducting state has been reported in polycrystalline samples; reduced specific heat jump at $T_{c}$ and apparent residual $T$-linear term in the limit of $T$=0 K. We have successfully grown high-quality single crystals of Lu$_{2}$Fe$_{3}$Si$_{5}$ using the floating-zone technique, and characterized its superconducting and normal state properties. The anomalies of the specific heat reported in polycrystalline samples are reproduced in the single crystals. In addition, we find a second drop of the specific heat below 1 K. We can fit the temperature dependence of the specific heat by assuming two superconducting gaps as in the case of MgB$_{2}$. Temperature dependence of Hall coefficient is nonmonotonic, and also suggests the presence of multiple bands in this compound.