Mechanism of high-Tc superconductivity based on tunneling measurements in cuprates

The main purpose of the paper is to present a brief summary of tunneling spectroscopy measurements performed in hole-doped cuprates and a brief description of the mechanism of high-Tc superconductivity based on the measurements. In cuprates, tunneling spectroscopy measurements show the presence of two superconducting energy gaps, Δp and Δc, and a normal-state pseudogap (a charge gap) Δcg(0)≃3Δp(0). On heating, Δc and Δp disappear at and above Tc, respectively. An anomaly found in I(V) characteristics indicates that the Cooper pairs in cuprates are soliton-like excitations.