As-grown superconducting Pr2CuO4 under thermodynamic constraints

Pr2CuO4 and other cuprates with square-planar coordinated copper require an annealing procedure for the induction of superconductivity. While this annealing procedure has prevented the origin of superconductivity in cuprates from being understood, it has been assumed that the antiferromagnetic insulating state is common among cuprate superconductors in their undoped state. Here, we show that appropriate synthesis conditions allow for the growth of as-grown superconducting Pr2CuO4 thin films by molecular beam epitaxy. The fact that Pr2CuO4 can be a superconductor in its as-grown state shows that thermodynamic rather than doping mechanisms are responsible for the different electronic ground state in electron-doped cuprates.