Mott Transition, Antiferromagnetism, and d -Wave Superconductivity in Two-Dimensional Organic Conductors

We study the Mott transition, antiferromagnetism, and superconductivity in layered organic conductors using the cellular dynamical mean-field theory for the frustrated Hubbard model. A d-wave superconducting phase appears between an antiferromagnetic insulator and a metal for t^'/t=0.3--0.7 or between a nonmagnetic Mott insulator (spin liquid) and a metal for t^'/t≥0.8, in agreement with experiments on layered organic conductors including κ-(ET)₂Cu₂(CN)₃. These phases are separated by a strong first-order transition. The phase diagram gives much insight into the mechanism for d-wave superconductivity. Two predictions are made.