Composition dependent polymorphism and superconductivity in Y{Rh,Ir}Ge

• Published in: Dalton transactions : an international journal of inorganic chemistry 2022-03, Vol.51 (12), p.4734-4748
• Main Authors: Feig, Manuel, Carrillo-Cabrera, Wilder, Bobnar, Matej, Simon, Paul, Curfs, Caroline, Levytskyi, Volodymyr, Tsirlin, Alexander A, Leithe-Jasper, Andreas, Gumeniuk, Roman
• Format: Article
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d2dt00167e

Polymorphism is observed in the Y 3+ x Rh 4 Ge 13− x series. The decrease of Y-content leads to the transformation of the primitive cubic Y 3.6 Rh 4 Ge 12.4 [ x = 0.6, space group Pm 3&cmb.macr; n , a = 8.96095(9) Å], revealing a strongly disordered structure of the Yb 3 Rh 4 Sn 13 Remeika prototype, into a body-centred cubic structure [La 3 Rh 4 Sn 13 structure type, space group I 4 1 32, a = 17.90876(6) Å] for x = 0.4 and further into a tetragonal arrangement (Lu 3 Ir 4 Ge 13 structure type, space group I 4 1 / amd , a = 17.86453(4) Å, a = 17.91076(6) Å) for the stoichiometric ( i.e. x = 0) Y 3 Rh 4 Ge 13 . Analogous symmetry lowering is found within the Y 3+ x Ir 4 Ge 13− x series, where the compound with Y-content x = 0.6 is crystallizing with La 3 Rh 4 Sn 13 structure type [ a = 17.90833(8) Å] and the stoichiometric Y 3 Ir 4 Ge 13 is isostructural with the Rh-analogue [ a = 17.89411(9) Å, a = 17.9353(1) Å]. The structural relationships of these derivatives of the Remeika prototype are discussed. Compounds from the Y 3+ x Rh 4 Ge 13− x series are found to be weakly-coupled BCS-like superconductors with T c = 1.25, 0.43 and 0.6, for x = 0.6, 0.4 and 0, respectively. They also reveal low thermal conductivity (