The iron-based intermetallic YFe2Ge2 stands out among transition metal compounds for its high Sommerfeld coefficient of the order of 100 mJ/(molK 2 ), which signals strong electronic correlations. A new generation of high quality samples of YFe2Ge2 show superconducting transition anomalies below 1.8 K in thermodynamic as well as transport measurements, establishing that superconductivity is intrinsic in this layered iron compound outside the known superconducting iron pnictide or chalcogenide families. The Fermi surface geometry of YFe2Ge2 resembles that of KFe2As2 in the high pressure collapsed tetragonal phase, in which superconductivity at temperatures as high as 10 K has recently been reported, suggesting an underlying connection between the two systems.

In the d‐electron system YFe2Ge2, an unusually high and temperature dependent Sommerfeld ratio of the specific heat capacity C /T ∼ 100 mJ/(mol K2) and an anomalous power law temperature dependence of the electrical resistivity ρ≃ρ0+AT3/2 signal Fermi liquid breakdown, probably connected to a close‐by quantum critical point. Full resistive transitions and DC diamagnetic screening fractions of up to 80% suggest that pure samples of YFe2Ge2 superconduct below 1.8 K. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

In the d-electron system YFe 2 Ge 2 , an unusually high and temperature dependent Sommerfeld ratio of the specific heat capacity C/T ∼ 100 mJ/(molK 2 ) and an anomalous power law temperature dependence of the electrical resistivity ρ ρ 0 + AT 3/2 signal Fermi liquid breakdown, probably connected to a close-by quantum critical point.Full resistive transitions, accompanied by DC diamagnetic screening fractions of up to 80% suggest that pure samples of YFe 2 Ge 2 superconduct below 1.8 K.