Hidden one-dimensional, strongly nested, and almost half-filled Fermi surface in Ba₂CuO₃+ᵧ superconductors

Abstract

All previous cuprate superconductors display a set of common features: (i) vicinity to a Cu Formula Presented configuration; (ii) separated Formula Presented planes; and (iii) superconductivity for doping Formula Presented. Recently, Li et al. [Proc. Natl. Acad. Sci. USA 116, 12156 (2019)PNASA60027-842410.1073/pnas.1900908116] challenged this picture by discovering “highly overdoped” superconducting Formula Presented. Using density-functional theory plus dynamical mean-field theory, we reveal a bilayer structure of Formula Presented of alternating quasi-two-dimensional (2D) and quasi-one-dimensional (1D) character. Correlations tune an interlayer self-doping leading to an almost half-filled, strongly nested, quasi-1D Formula Presented band, which is prone to strong antiferromagnetic fluctuations, possibly at the origin of superconductivity in Formula Presented.