Abstract
We have synthesized La2−x Sr x CuO4 thin films using atomic layer-by-layer molecular beam epitaxy (ALL-MBE). The films are high-quality—singe crystal, atomically smooth, and very homogeneous. The critical temperature (T c) shows a very little (<1 K) variation within a film of 10×10 mm 2 area. The large statistics (over 2000 films) is crucial to discern intrinsic properties. In these films, we have measured the absolute value of the magnetic penetration depth λ with the accuracy better than 1 % and mapped densely the entire overdoped side of the La2−x Sr x CuO4 phase diagram. A new scaling law is established accurately for the dependence of T c on the superfluid density. The scaling we observe is incompatible with the standard Bardeen-Cooper-Schrieffer picture and points to local pairing.
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This research was done at the Brookhaven National Laboratory and was supported by the U.S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division. X.H. is supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF4410.
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Božović, I., He, X., Wu, J. et al. The Demise of Superfluid Density in Overdoped La2−x Sr x CuO4 Films Grown by Molecular Beam Epitaxy. J Supercond Nov Magn 30, 1345–1348 (2017). https://doi.org/10.1007/s10948-016-3819-1
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DOI: https://doi.org/10.1007/s10948-016-3819-1