Optical and magneto-optical response of a doped Mott insulator

Abstract

We study the optical, Raman, and ac Hall response of the doped Mott insulator within the dynamical mean-field theory $(d=\ensuremath{\infty})$ for strongly correlated electron systems. The occurrence of the isosbectic point in the optical conductivity is shown to be associated with the frequency dependence of the generalized charge susceptibility. We compute the Raman response, which probes the fluctuations of the ``stress tensor,'' and show that the scattering is characterized by appreciable incoherent contributions. The calculated ac Hall constant and Hall angle also exhibit the isosbectic points. These results are also compared with those obtained for a non-FL metal in $d=\ensuremath{\infty}.$ The role of low-energy coherence (FL) or incoherence (non-FL) in determining the finite frequency response of strongly correlated metals in $d=\ensuremath{\infty}$ is discussed in detail. As an application of interest, we compute the dielectric figure-of-merit (DFOM), a quantity that is of potential importance for microwave device applications. We demonstrate explicitly that systems near the filling driven Mott transition might be good candidates in this respect, and discuss the influence of real-life factors on the DFOM.