Phase separation and pseudogap in electron-doped cuprates: A variational cluster perturbation analysis

Abstract

We study the quantum transition from an antiferromagnet to a superconductor in the single-band Hubbard model with parameters appropriate to describe electron- and hole-doped cuprates by means of variational cluster perturbation theory, a method appropriate to deal with strongly-correlated systems. In both cases, our results produce phase separation into a mixed antiferromagnetic-superconducting phase at low doping and a pure superconducting (SC) phase at higher doping. However, in the electron-doped case the energy scale for phase separation is an order of magnitude smaller than for hole doping. This behavior can be understood in terms of the different Fermi-surface evolution in p- and n-doped materials upon doping. We argue that this behavior can be related to the different pseudogap and SC transition scales in hole- and electron-doped materials.