Resonant two-magnon Raman scattering in two-dimensional Mott insulators

Abstract

We investigate the resonant two-magnon Raman scattering in two-dimensional Mott insulators by using a half-filled extended Hubbard model with the second and third nearest-neighbour hopping terms, t′ and t″, and the nearest-neighbour Coulomb interaction, V. By performing numerical diagonalization calculations for a small cluster, we find that the model can reproduce the experimental features that the Raman intensity is enhanced when the incoming photon energy ω i is not near the absorption edge but well above it. We also find that the t′, t″, and V terms bring about less effect on resonant behaviours in the Raman scattering.