Spin and orbital correlations of a photoexcited state of a two-orbital Hubbard model on a 2 × 2 × 2 cluster

We study the physical properties of a photoexcited state of a two-orbital Hubbard model at quarter filling on a 2 × 2 × 2 tetragonal cluster. Numerical analysis by using the Lanczos diagonalization method demonstrates that the dominant spin correlation drastically changes upon photoexcitation from the C-type antiferro (AF) correlation of the ground state to the A-type AF correlation of the photoexcited state. The largest orbital correlation also changes upon photoexcitation, although several correlations are of comparable order for both the states. Furthermore, the photoinduced changes of the correlations are closely related to the dynamics of photocarriers, which spread over layers of the cluster.