Speaker
Description
Cuprates are prototypical for high-temperature superconductivity and host a vast family of com-
pounds. Recently, the new Ba$_2$CuO$_{3+y}$ cuprate superconductor has been discovered, which challenges the previous physics picture in other cuprate superconductors by (1) exhibiting superconducting only in a narrow ’highly overdoped’ doping region ($y$=0.2) (2) hosting a different Fermi-surface; To shed light onto this most unusual cuprate we use density-functional-theory (DFT) combined with dynamical-mean-field-theory (DMFT) and reveal that correlation effects drive a charge-transfer between CuO$_{1.5}$ and CuO planes in Ba$_2$CuO$_{3.2}$, which leads to a quasi 1D $d_{y^2-z^2}$ band, instead of the common 2D $d_{x^2-y^2}$. This discovery offers a new theoretical explanation to understand the recently discovered superconductor Ba$_2$CuO$_{3.2}$.
