Features in Quasi-particle Excitations and Tunneling Spectradue to Coupling to Spin Fluctuations in High-T_c Cuprates

In a self-consistent mean-field treatment of the two-dimensional t-t'-J model, we theoretically examine the coupling of in-plane quasi-particles to the antiferromagnetic spin fluctuations in high-T_c superconductors, which renormalizes the fermionic self-energy. We reproduce the characteristic peak-dip-hump structure observed not only in angle-resolved photoemission spectroscopy, but also in supperconductor-insulator-normal metal junction and scan tunneling microscopy experiments. We consider the evolution of this structure with doping. It is shown that this kind of coupling can account for many anomalous properties of high-T_c superconductor in superconducting states.