Pseudogap induced by superconducting fluctuation and anomalous metallic phase in the high- Tc superconducting materials

Abstract

Using the d–p model, we demonstrate that spin fluctuation and pseudogap induced by superconducting fluctuation influence each other and play key roles in the determination of the phase diagram observed in high- T c superconducting materials. We calculate superconducting transition temperature T c, NMR relaxation rate 1/ T 1 T and single particle spectra by treating both the superconducting fluctuation and spin fluctuation in a consistent fashion. As temperature decreases, 1/ T 1 T increases at high temperatures, while it reaches a maximum followed by sharp drop at the underdoped region, which is due to evolution of the pseudogap in the single-particle spectra. The evolution is also consistent with those of ARPES experiments.