Quantum geometric contribution to Raman spectroscopic response in multi-orbital Mott insulators

Raman spectroscopy is a powerful tool for probing low-energy electronic phenomena. It provides insights into elementary excitations of materials and permits symmetry-selective probing of collective modes via photon polarizations. However, conventional approaches to modeling spectroscopies of Mott insulators often neglect the multi-band nature of real materials. In systems where electronic bands have mixed orbital character, quantum geometric effects, characterized by the Berry curvature and quantum metric, can lead to corrections to effective Coulomb interactions and light-matter coupling in the low-energy subspace. In this talk, we calculate their influence on the Raman scattering cross-section via explicitly integrating out remote bands, identifying a quantum geometric contribution to the Raman response. Our findings reveal how quantum geometric effects alter peak intensities and necessitate adjustments in the theoretical modeling of multi-orbital systems.