  We present a spatial and wave-vector resolved study of the electronic
structure of micron sized ferroelectric domains at the surface of a BaTiO3(001)
single crystal. The n-type doping of the BaTiO3 is controlled by in-situ vacuum
and oxygen annealing, providing experimental evidence of a surface
paraelectric-ferroelectric transition below a critical doping level. Real space
imaging of photoemission threshold, core level and valence band spectra show
contrast due to domain polarization. Reciprocal space imaging of the electronic
structure using linearly polarized light provides unambiguous evidence for the
presence of both in and out-of plane polarization with two and fourfold
symmetry, respectively. The results agree well with first principles
calculations.
