Shubnikov-de Haas Oscillations in the Electron-doped Cuprate Superconductors*

We have studied the electronic structure of electron-doped cuprate superconductors via measurements of Shubnikov-de Haas oscillations in thin films with magnetic fields up to 80 T and in temperatures from 0.7 K to 20 K. In optimally and overdoped Pr$_{\mathrm{2-x}}$Ce$_{\mathrm{x}}$CuO$_{\mathrm{4}}$ and optimally doped La$_{\mathrm{2-x}}$Ce$_{\mathrm{x}}$CuO$_{\mathrm{4}}$, quantum oscillations indicate the presence of a small Fermi surface, indicative of electronic reconstruction. These measurements show that superconductivity emerges from a similar electronic state in all of the electron-doped cuprates. We will discuss low-temperature signatures of residual magnetic fluctuations that may connect the electronic structure to the nearby quantum critical point.