High-Energy Magnetic Excitations in the Cuprate Superconductor Bi₂Sr₂CaCu₂O_8+δ: Towards a Unified Description of Its Electronic and Magnetic Degrees of Freedom

We investigate the high-energy magnetic excitation spectrum of the high-Tc cuprate superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) using Cu L3 edge resonant inelastic x-ray scattering. Broad, dispersive magnetic excitations are observed, with a zone boundary energy of ~300 meV and a weak dependence on doping. These excitations are strikingly similar to the bosons proposed to explain the high-energy ‘‘kink’’ observed in photoemission. A phenomenological calculation of the spin response, based on a parametrization of the the angle-resolved photoemission spectroscopy derived electronic structure and Yang-RiceZhang quasiparticles, provides a reasonable prediction of the energy dispersion of the observed magnetic excitations. These results indicate a possible unified framework to reconcile the magnetic and electronic properties of the cuprates and we discuss the advantages and disadvantages of such an approach