On the nature of pairing in the two-dimensional t-J model

Using an extended dynamical cluster approximation, we study the nature of superconductivity in the two-dimensional t-J model. Short-ranged correlations within a finite cluster are treated explicitly, while the effects of longer-ranged physics are incorporated on the mean-field level with self-consistent Fermionic and Bosonic fields. To solve this cluster problem, we employ a non-crossing approximation which allows for transitions to the symmetry-broken state. At sufficiently low temperatures we find a stable superconducting solution with d-wave order parameter. Upon pairing, the exchange energy is lowered, consistent with an exchange-based pairing mechanism.