| The electronic structure of optimally doped Bi2(Sr2-xLax)CuO6+δ（La-Bi2201） high temperature superconductor has been investigated by the vacuum ultra-violet high resolution laser-based angle-resolved photoemission spectroscopy. Detailed momentum-dependent measurement shows that there exist three many-body coupling modes, i.e.. 59 meV, 40 meV and 22 meV in both superconducting state and normal state. They show weak momentum dependence and their energy scale do not shift with the opening of superconducting gap. We also study the temperature evolution of multiple modes in the electron self-energy at nodal direction. When the temperature decreases from “normal†metal state to pseudogap state, the multiple modes begin to emerge. When entering the superconducting state due to the decrease of temperature, they get pronounced and their energy scale do not shift with the opening of superconducting gap. |
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