Correlated electronic structure of the high-temperature superconductor Ba 2 CuO 3 + δ

Cuprate superconductors have attracted extensive attention due to high critical temperatures. Conventional cuprates typically contain perfect CuO₂ planes, which are considered as a key factor to superconductivity since the superconductivity takes place in them. However, in Ba₂CuO₃+ with =0. 2 and O-depleted CuO₂ planes, superconductivity still arises even with a transition temperature as high as 73 K. Using combined density functional theory and dynamical mean-field theory calculations, we investigated the electronic correlation and electronic structure of Ba₂CuO₃. ₂₅ with alternating quasi-one-dimensional (quasi-1D) CuO planes and O-depleted CuO₂ planes. We find that although different from the usual cuprates, the Cu atoms are still dominated by a 3d^9 configuration and the system is of a new kind of correlated single-orbital physics. The quasi-1D CuO planes, composed of parallel Cu-O chains, are slightly hole-doped quasi-1D Mott insulators, while the O-depleted CuO₂ planes are more hole doped, with a two-dimensional correlated electronic structure, and may host superconductivity.