by in-situ doping*

Cuprate high temperature superconductors have been studied 40 years now, but there still are many questions unresolved. A systematic study on cuprates is necessary to figure out these questions. Recently,we succeed in tuning the doping level of Bi₂Sr₂CaCu₂O_8+x (Bi2212) in-situ by ozone annealing and vacuum annealing. Compared to the previously angle-resolved photoemission spectroscopy (ARPES) works which carried on different doped samples, our results are more reliable because the we detect the same surface. We tune the doping in a large range, from 0.05 to 0.25, almost including the whole superconducting region. Using in-situ high resolution ARPES, we get the doping evolution of gap, kink and Quasiparticle information. Our work give a overall look of cuprate superconductivity and is helpful to establish the electronic phase diagram in Bi2212 that can be extended to other cuprate superconductors.