Hole dynamics in the copper oxide planes (invited) (abstract)

The physics of a hole doped into the Mott insulating state of the CuO₂ planes is studied in a large variational space. The hole quasiparticle that forms is quite different from a free electron by virtue of the cloud of spin flips (with respect to the background antiferromagnet) that it carries with it. The momentum dependence of the quasiparticle energy is unusual: ε(k) is lowest at nonzero momentum, and has an anisotropic dispersion. At finite doping, the quasiparticles are assumed to fill the rigid band described by the single hole ε(k), forming a weakly interacting Fermi gas. Normal state properties of the high temperature superconducting oxides, such as La_2-xSr_xCuO₄, are calculated in the relaxation time approximation. Good agreement with experiment is obtained for the magnetic susceptibility, Hall coefficient, thermopower, specific heat, and plasma frequency as a function of both doping x and temperature¹.