Non-Fermi-liquid-like behaviors of the CuO 2 model of the high- Tc systems

Abstract

We have studied the non-Fermi-liquid properties of the doped three-band CuO 2 model for the high- T c superconductors in the infinite U d slave-boson approach. The Green's functions of quasiparticles (d- and p-characters) as well as of the Cu d-electron for this model have been derived for the first time in the closed form by taking into account all the self-energies to order O(1/ N). We have examined the energy and temperature dependences of the imaginary parts of the self-energies and the spectral functions of Cu d- and oxygen p-electrons. It is found that charge fluctuations of quasiparticles due to constraint-field bosons give rise to the anomalous self-energy of quasiparticles which is consistent with experiment. Here the imaginary part of the d-electron self-energy exhibits a crossover from a quadratic (canonical Fermi liquid) to linear (non-canonical Fermi liquid) energy dependence above a small energy scale ω c≈0.01 eV for the hole doping (δ≈0.14), while the p-electron self-energy remains to be Fermi-liquid-like and does not contribute to the anomalous behavior. The origin of this characteristic energy scale ω c is discussed. The spectral functions of quasiparticles are asymmetric and are similar to the predictions of the marginal Fermi-liquid hypothesis.