Electronic inhomogeneity and competing phases in electron-doped superconducting Pr0.88LaCe0.12CuO4-δ -: art. no. 100502

We use neutron scattering to demonstrate that electron-doped superconducting Pr0.88LaCe0.12CuO4-delta in the underdoped regime is electronically phase separated in the ground state, showing the coexistence of a superconducting phase with a three-dimensional antiferromagnetically ordered phase and a quasi-two-dimensional spin-density wave modulation. The Neel temperature of both antiferromagnetic phases decreases linearly with increasing superconducting transition temperature (T-c) and vanishes when optimal superconductivity is achieved. These results indicate that the electron-doped copper oxides are close to a quantum critical point, where the delicate energetic balance between different competing states leads to microscopic heterogeneity.