Hole pocket–driven superconductivity and its universal features in the electron-doped cuprates

Abstract

After three decades of intensive research attention, the emergence of superconductivity in cuprates remainsan unsolved puzzle. One major challenge has been to arrive at a satisfactory understanding of the unusualmetallic"normal state"from which the superconducting state emerges upon cooling. A second challenge hasbeen to achieve a unified understanding of hole- and electron-doped compounds. Here, we report detailedmagnetoresistance measurements for the archetypal electron-doped cuprate Nd2−xCexCuO4+dthat, in combina-tion with previous data, provide crucial links between the normal and superconducting states and between theelectron- and hole-doped parts of the phase diagram. The characteristics of the normal state (magnetoresistance,quantum oscillations, and Hall coefficient) and those of the superconducting state (superfluid density and uppercritical field) consistently indicate two-band (electron and hole) features and point to hole pocket-driven super-conductivity in these nominally electron-doped materials. We show that the approximate Uemura scaling be-tween the superconducting transition temperature and the superfluid density found for hole-doped cupratesalso holds for the small hole component of the superfluid density in electron-doped cuprates.