Superconducting dome with extended s-wave pairing symmetry in the heavily hole-overdoped copper-oxide planes

Abstract

We analyze the two-orbital (with dx2−y2 and d3z2−r2 orbitals) analog of the t−J−U model as applied to the description of the copper-oxide monolayer deposited on the Bi2Sr2CaCu2O8+δ substrate (CuO2/BSCCO). We show that an extended s-wave superconducting dome appears in the heavily hole-overdoped regime of the model, with dominant contribution to the pairing coming from the d3z2−r2 orbitals. Also, the lower critical doping for the appearance of the SC state concurs with the Lifshitz transition after which the hole-like Fermi pockets are created around the M points in the Brillouin zone. The obtained results are in accord with the recent experimental result [cf. Zhong et al., Sci. Bull. 61, 1239 (2016)]. An analogous two-band description is also analyzed in the context of the Ba2CuO4−y bulk compound, where the heavily hole-overdoped situation is believed to be reached [cf. Li et al., Proc. Natl. Acad. Sci. USA 116, 12156 (2019)]. As we show, a two-dome structure can be realized in such system with the d- and s-wave symmetries of the gap, corresponding to the low hole-doping and heavily hole-overdoped cases, respectively.

Source-reported materials — not catalogue approval

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