Superconductivity in Y₃Ru₄Ge₁₃ and Lu₃Os₄Ge₁₃: A comparative study

Abstract

A variety of unconventional superconductors have low carrier density as a\ncommon factor. However, the underlying mechanism of superconductivity in such\nlow carrier density systems is not well understood. Besides, small carrier\ndensity is an unfavourable component for conventional superconductivity as\ndescribed by the Bardeen-Cooper-Schrieffer (BCS) theory. Therefore, studying\nlow carrier density systems can lead to a better understanding in such systems.\nIn this paper, we report superconductivity property studies in low carrier\ndensity systems, Y$_3$Ru$_4$Ge$_{13}$ and Lu$_3$Os$_4$Ge$_{13}$, using various\nexperimental techniques. Single crystals of Y$_3$Ru$_4$Ge$_{13}$ and\nLu$_3$Os$_4$Ge$_{13}$ have been grown using the Czochralski crystal pulling\nmethod in a tetra-arc furnace. The x-ray diffraction experiment reveals that\nboth compounds crystallize in cubic structure {(space group $\\it{Pm3n}$, no.\n223)}. The transport, magnetization and heat capacity measurements show that\nY$_3$Ru$_4$Ge$_{13}$ single crystal undergoes a superconducting transition at\n2.85~K, whereas, Lu$_3$Os$_4$Ge$_{13}$ becomes superconductor at 3.1~K.\n