Exact theory for electronic Raman scattering of correlated materials in infinite dimensions

A wide variety of strongly correlated materials including SmB6, FeSi, and the underdoped cuprates display anomalous behavior in their Raman response, which includes a low-temperature transfer of spectral weight from low to high energy ~as T is reduced! and the appearance of an isosbestic point ~a characteristic frequency where the Raman response is independent of temperature!. We illustrate how these features appear in the Raman response of the infinite-dimensional Hubbard model, which is the simplest system to undergo the Mott transition from a Fermi liquid phase. We find that the qualitative behavior in the insulating phase is model independent, and that a number of new features arise as one approaches the metal-insulator transition from the Fermi-liquid phase. Such behavior has not yet been seen in experiment. We propose a number of different systems that are likely to show these new anomalies.