Role of oxygen-oxygen hopping in the three-band copper-oxide model: Quasiparticle weight, metal insulator and magnetic phase boundaries, gap values, and optical conductivity

We investigate the effect of oxygen-oxygen hopping on the three-band copper-oxide model relevant to high-T_c cuprates, finding that the physics is changed only slightly as the oxygen-oxygen hopping is varied. The location of the metal-insulator phase boundary in the plane of interaction strength and charge-transfer energy shifts by ~0.5 eV or less along the charge-transfer axis, the quasiparticle weight has approximately the same magnitude and doping dependence, and the qualitative characteristics of the electron-doped and hole-doped sides of the phase diagram do not change. The results confirm the identification of La₂CuO₄ as a material with an intermediate correlation strength. However, the magnetic phase boundary as well as higher energy features of the optical spectrum are found to depend on the magnitude of the oxygen-oxygen hopping. We compare our results to previously published one-band and three-band model calculations. © 2011 American Physical Society.