Magnetic and transport properties of a coupled Hubbard bilayer with electron and hole doping

The single band, two-dimensional Hubbard Hamiltonian has been extensively studied as a model for high temperature superconductivity. While quantum Monte Carlo simulations within the dynamic cluster approximation are now providing considerable evidence for a d-wave superconducting state at low temperature, such a transition remains well out of reach of finite lattice simulations because of the "sign problem." We show here that a bilayer Hubbard model, in which one layer is electron doped and one layer is hole doped, can be studied to lower temperatures and exhibits an interesting signal of d-wave pairing. The results of our simulations bear resemblance to a recent report on the magnetic and superconducting properties of Ba2Ca3Cu4O8F2 which contains both electron and hole doped CuO2 planes. We also explore the phase diagram of bilayer models in which each sheet is at half-filling.