Pressure effects on the superconducting thin film Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$

Abstract

We report electrical resistivity measurements on a high-quality Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ thin film ($x=0.4$) under pressure. The superconducting transition temperature (=39.95 K) of the optimally-doped thin film shows a dome shape with pressure, reaching a maximal value 40.8 K at 11.8 kbar. The unusually high superconducting transition temperature and its anomalous pressure dependence are ascribed to a lattice mismatch between the LaAlO${}_3$ substrate and the thin film. The local temperature exponent of the resistivity ($n=d\text{ln}\Delta \rho /d\text{ln}T$) shows a funnel shape around the optimal pressure, suggesting that fluctuations associated with the anomalous normal state are responsible for high-temperature superconductivity.

To appear in Appl. Phys. Lett

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Cited by in corpus (1)

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