Composition dependence of bulk superconductivity in YFe2Ge2

Jiasheng Chen; Monika B. Gamża; Konstantin Semeniuk; F. Malte Grosche

doi:10.1103/PhysRevB.99.020501

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Composition dependence of bulk superconductivity in YFe2Ge2

Jiasheng Chen, Monika B. Gamża, Konstantin Semeniuk, F. Malte Grosche

DOI 10.1103/PhysRevB.99.020501 · Physical Review B

T1

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Abstract

In the layered iron-based superconductor YFe2Ge2, a high Sommerfeld ratio of ∼100mJ/molK2 and a T3/2 temperature dependence of the electrical resistivity at low temperature T indicate strong electronic correlations and point toward an unconventional pairing state. We have investigated the role of composition and annealing conditions in optimizing the growth of high-quality YFe2Ge2. Our findings confirm that bulk superconductivity is observed in samples with disorder scattering rates less than 2kBTc/ℏ. Fe deficiency on the Fe site is identified as the dominant source of disorder, which can be minimized by precipitating from a slightly iron-rich melt, followed by annealing.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YFe2Ge2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.87	Pressure not reported	midpoint
YFe2Ge2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure not reported	onset
LaFeSiH Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown