Electronic Raman scattering in correlated materials: exact treatment of nonresonant, mixed, and resonant scattering with dynamical mean field theory

摘要

We solve for the electronic Raman scattering response functions on aninfinite-dimensional hypercubic lattice employing dynamical mean field theory.This contribution extends previous work on the nonresonant response to includethe mixed and resonant contributions. We focus our attention on the spinlessFalicov-Kimball model, where the problem can be solved exactly, and the systemcan be tuned to go through a Mott-Hubbard-like metal-insulator transition.Resonant effects vary in different scattering geometries, corresponding to thesymmetries of the charge excitations scattered by the light. We do find thatthe Raman response is large near the double resonance, where the transferedfrequency is close to the incident photon frequency. We also find a jointresonance of both the charge-transfer peak and the low-energy peak when theincident photon frequency is on the order of the interaction strength. Ingeneral, the resonance effects can create order of magnitude (or more)enhancements of features in the nonresonant response, especially when theincident photon frequency is somewhat larger than the frequency of thenonresonant feature. Finally, we find that the resonant effects also exhibitisosbestic behavior, even in the A1g and B2g sectors, and it is most prominentwhen the incident photon frequency is on the order of the interaction energy.