Hole superconductivity in the electron-doped superconductor Pr_2−xCe_xCuO₄

We measure the resistivity and Hall angle of the electron-doped superconductor Pr_2−xCe_xCuO₄ as a function of doping and temperature. The resistivity ρ_xx at temperatures 100 K<T<300 K is mostly sensitive to the electrons. Its temperature behavior is doping independent over a wide doping range and even for nonsuperconducting samples. On the other hand, the transverse resistivity ρ_xy, or the Hall angle θ_H, where cot(θ_H)=ρ_xx∕ρ_xy, is sensitive to both holes and electrons. Its temperature dependence is strongly influenced by doping, and cot(θ_H) can be used to identify optimum doping (the maximum T_c) even well above the critical temperature. These results lead to a conclusion that in electron doped cuprates holes are responsible for the superconductivity.