Ab initio description of the Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ electronic structure

Abstract

Bi-Sr-Ca-Cu-O superconductors are important materials for both fundamental research and applications. As in other cuprates, the superconducting phase in these Bi-compounds lies close to an antiferromagnetic phase. Density functional theory calculations based on the strongly-constrained-andappropriately-normed (SCAN) exchange correlation functional in Bi2Sr2CuO6 and Bi2Sr2CaCu2O8 reveal the persistence of magnetic moments on the copper ions for oxygen concentrations ranging from the pristine phase to the optimally hole-doped compound. We also find the existence of ferrimagnetic solutions in the heavily doped compounds, which are expected to suppress superconductivity.