| Using the recently proposed Variational Cluster Approach (VCA), we study the competition between d-wave superconductivity and antiferromagnetism in hole- and electron-doped cuprates. The occurence of two inhomogeneous phases is considered: First we discuss the possibility of phase separation with a mixed SC+AF phase at low doping, and a pure SC phase at higher doping. Second we show an instability of the Hubbard model towards a checkerboard-like structure within the pure SC phase. Furthermore we investigate the gap structure of the superconducting gap. We find that our results within the Hubbard model using a spin-modulated pairing mechanism can naturally explain the different energy scales found in recent ARPES experiments. |
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