Multigap Superconductivity at 5.4 K in $\beta$-Bi$_2$Pd

We report the superconducting properties of new multigap superconductor Bi$_2$Pd($\beta$-Bi$_2$Pd; space group: $I4/mmm$)[1]. $\beta$-Bi$_2$Pd single crystals were grown via a melt-growth method. The temperature dependences of the electrical resistivity and the magnetic susceptibility reveal that the superconducting transition occurs at 5.4 K in the $\beta$-Bi$_2$Pd single crystal. This value is greater than the value of 4.25 K reported in the previous paper [2]. Here, it is interesting to note that the $T_{\mathrm{c}}$ of $\beta$-Bi$_2$Pd reported here is almost the same as that of Pd-intercalated Bi$_2$Te$_3$ with a very small superconducting volume fraction ($<1 \%$) in ref. [3], where the possibility that the topological insulator Bi$_2$Te$_3$ can be made into an SC by Pd intercalation between the Bi$_2$Te$_3$ layers is argued. In addition, the temperature dependences of the upper critical magnetic field and the specific heat suggest that $\beta$-Bi$_2$Pd is a multiple-band/multiple-gap superconductor. \\[4pt] [1] Y. Imai \textit{et al.}, J. Phys. Soc. Jpn. 81 (2012) 113708. (arXiv: 1207.5905.)\\[0pt] [2] N.~E. Alekseevski \textit{et al.}, Zh. Eksp. Teor. Fiz. 27 (1954) 125.\\[0pt] [3] Y.~S. Hor \textit{et al.}, J. Phys. Chem. Sol. 72 (2011) 572.