  A central question in the high temperature cuprate superconductors is the
fate of the parent Mott insulator upon charge doping. Here we use scanning
tunneling microscopy to investigate the local electronic structure of lightly
doped cuprate in the antiferromagnetic insulating regime. We show that the
doped charge induces a spectral weight transfer from the high energy Hubbard
bands to the low energy in-gap states. With increasing doping, a V-shaped
density of state suppression occurs at the Fermi level, which is accompanied by
the emergence of checkerboard charge order. The new STM perspective revealed
here is the cuprates first become a charge ordered insulator upon doping.
Subsequently, with further doping, Fermi surface and high temperature
superconductivity grow out of it.
