Doping and defects in YBa_(2)Cu_(3)O_(7): Results from hybrid density functional theory

摘要

Modified orbital occupation and inhomogeneous charge distribution in high-T_(c) oxide compounds due to doping and/or defects play a huge role for the material properties. To establish insight into the charge redistribution, we address metallic YBa_(2)Cu_(3)O_(7) in two prototypical configurations: Ca doped (hole doping) and O deficient (electron doping). By means of first principles calculations for fully relaxed structures, we evaluate the orbital occupations. We find that the change of the charge density, in particular in the CuO_(2) planes, shows a complex spatial pattern instead of the expected uniform (de-)population of the valence states.