Cellular-dynamical mean-field theory of the competition between antiferromagnetism and d-wave superconductivity in the two-dimensional Hubbard model

Cellular dynamical mean field theory is used to study the competition of antiferromagnetism and d-wave superconductivity at zero-temperature in the two-dimensional Hubbard model. The outcome strongly depends on the value of the interaction. At strong coupling (U >= 8t) a first-order transition takes place as a function of doping between pure antiferromagnet and pure superconductor. At weak-coupling instead (U <= 8t) the groundstate has both antiferromagnetic and d-wave long-range order, and the system smoothly evolves from one phase to the other. The first-order transition at large interactions is accompanied by a phase separation. (c) 2006 Elsevier B.V. All rights reserved.