The cubic compounds R3T4Ge13 (R = non-magnetic Y or Lu, and T = Co, Rh, Os or Ir) are superconducting, with critical temperatures below 3 K. Interestingly, a Ge site splitting occurs in these germanide superconductors, and it appears to result in a large atomic displacement parameter ratio. In turn, these seems to correlate with unusually large, semiconducting-like normal state resistivity in these superconductors.
R3T4Ge13 (R = Lu, Y; T = Co, Rh, Os, Ir)
Despite the success of BCS theory in explaining conventional superconductivity, many questions remain both about conventional and high temperature superconductors. We are particularly interested in answering questions regarding the competition between superconductivity and other magnetic or electronic ground states, as well as to clarify the role of the crystal structure in the occurrence of unconventional superconductivity.
B. K Rai, I. W. H. Oswald, J. K. Wang, G. T. McCandless, J. Y. Chan, and E. Morosan, "Superconductivity in Single Crystals of Lu3 T 4Ge13–x (T= Co, Rh, Os) and Y3 T 4Ge13–x (T= Ir, Rh, Os)" Chem. Mater. 27, 2488 (2015)
Liang L. Zhao, Stefan Lausberg, H. Kim, M. A. Tanatar, Manuel Brando, R. Prozorov and E. Morosan "Type-I superconductivity in YbSb2 single crystals" Phys. Rev. B 85, 214526 (2012)
E. Svanidze and E. Morosan "Type-I superconductivity in ScGa3 and LuGa3 single crystals" Phys. Rev. B 85, 174514 (2012)
Most elemental superconductors are type I, while the vast majority of know superconducting compounds are type II. We confirmed that YbSb2 was one such example, and discovered two other type I superconducting binaries, ScGa3 and LuGa3.