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Origin of superconducting carriers in "non-doped" T'- (La,RE)2CuO4 (RE = Sm, Eu, Gd, Tb, Lu, and Y) prepared by molecular beam epitaxy

M. Noda·A. Tsukada·H. Yamamoto·M. Naito
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Abstract

We have performed a systematic investigation of the variations of the lattice constants with substituent rare-earth element concentration x in the nominally undoped superconductors T'-(La3+)2-x(RE3+)xCuO4 (RE = Sm, Eu, Gd, Tb, Lu, and Y), which we have recently discovered using MBE. The results show both the in-plane and out-of-plane lattice constants (a0 and c0) linearly decrease with x, whose extrapolation to x = 2 agrees well with the reported a0 and c0 values for each T'-RE2CuO4. This behavior is what one would expect simply from the ionic size difference between La3+ and RE3+. The absence of the Cu-O bond stretching due to electron-doping, which is commonly observed in electron-doped T' and infinite-layer superconductors, implies that electron doping via oxygen deficiencies is, at least, not a main source of charge carriers.

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M. Noda, A. Tsukada, H. Yamamoto, M. Naito. 2005-01-28. Origin of superconducting carriers in "non-doped" T'- (La,RE)2CuO4 (RE = Sm, Eu, Gd, Tb, Lu, and Y) prepared by molecular beam epitaxy. https://doi.org/10.1016/j.physc.2005.02.034

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