Doublon dynamics of the Hubbard model on a triangular lattice

We study the dynamics of doublons in the half-filled Hubbard model on the triangular lattice by using cellular dynamical mean-field theory. Investigating the nearest-neighbor dynamical correlations, we demonstrate that a nearest-neighbor doublon-holon pair shows a strong attraction, in particular in the insulating phase. The nearest-neighbor doublon and holon dynamics obtained indicate that the characteristic time scales inversely with the Coulomb interaction in the short-time region in both the metallic and insulating phases. We find that the metallic phase has larger fluctuations in their dynamics. In the long-time region, the metallic phase has persistent fluctuations in various nearest-neighbor configurations, while the fluctuations are vanishingly small in the insulating phase. We also calculate the on-site dynamical correlation of doublons and find that the lifetime of the doublon is longer in the metallic phase than in the insulating phase.