Fermiology of the undoped cuprate superconductor Pr$_{2}$CuO$_{4}$

Recent advances in molecular beam epitaxy growth and preparation of cuprate thin films indicate that annealing can be employed to minimize apical oxygen defects. For Pr$_{2}$CuO$_{4}$ the resulting square planar coordinated structure exhibits a 25~K superconducting transition in the absence of doping. This calls into question whether a Mott insulating groundstate is the relevant description of the square-planar parent phase of the electron-doped cuprate superconductors. We present high field (\textgreater 90~T) measurements of magnetic quantum oscillations --~the first observation of it's kind for a cuprate thin film. The oscillation frequency and effective mass are consistent with the reconstructed Fermi surface of the electron-doped cuprate Nd$_{2-x}$Ce$_{x}$CuO$_{4}$. The combination of a reconstructed bandstructure and the occurrence of metalicity at zero doping is consistent with a Slater picture of band magnetism, indicating that the ``doped Mott insulator'' paradigm may not apply in this system.