Band crossover and magnetic phase diagram of the high-Tc superconducting compound Ba2CuO4−δ

Abstract

We present the influences of electronic and magnetic correlations and doping on the ground-state properties of the recently discovered superconductor Ba2CuO4−δ by utilizing the rotationally invariant slave-boson method. Starting with an effective two-orbital Hubbard model [Scalapino et al., Phys. Rev. B 99, 224515 (2019)], we demonstrate that with increasing doping concentration, the paramagnetic (PM) system evolves from a two-band character to single band around the electron filling n=2.5, with the band nature of the d3z2−r2 and dx2−y2 orbitals to the d3z2−r2 orbital, slightly affected when the electronic correlation U varies from 2 to 4 eV. Considering the magnetic correlations, the system displays one antiferromagnetic (AFM) metallic phase in 2<n<2.14 and a PM phase in n>2.14 at U=2eV, or two AFM metallic phases in 2<n<2.52 and 2.74<n<3, and a PM phase in 2.52<n<2.74, respectively, at U=4eV. Our results show that near the realistic superconducting state around n=2.6 the intermediate correlated Ba2CuO3,2 should be of single-band character. The s-wave superconducting pairing strength becomes significant when U>2eV, and crosses over to d wave when U>2.2eV.

Source-reported materials — not catalogue approval

Similar papers