Resonant Enhancement of Inelastic Light Scattering in Strongly Correlated Materials

We use dynamical mean field theory to find an exact solution for inelastic light scattering in strongly correlated materials such as those near a quantum-critical metal-insulator transition. We evaluate the results for $\mathbf{q}=0$ (Raman) scattering and find that resonant effects can be quite large, and yield a double resonance, a significant enhancement of nonresonant scattering peaks, a joint resonance of both peaks when the incident photon frequency is on the order of $U$, and the appearance of an isosbestic point in all symmetry channels for an intermediate range of incident photon frequencies.

Figure 1

Raman response function for different channels. We take $U=2$, $T=0.5$, and choose ${\omega }_i=0.5-4.5$ in steps of 0.5 (the different line thicknesses correspond to different ${\omega }_i$’s).

Figure 2

Raman response function for $U=2$ and ${\omega }_i=2$ for different channels at $T=1$, $T=0.5$, $T=0.2$, and $T=0.05$. The temperature decreases as the lines are made thicker.

Figure 3

Raman response function for $U=2$ and $\Omega =2$ for different channels at $T=1$, $T=0.5$, $T=0.2$, and $T=0.05$. The temperature decreases as the lines are made thicker.

Figure 4

Raman response function for $U=2$ and $\Omega =0.5$ for different channels at $T=1$, $T=0.5$, $T=0.2$, and $T=0.05$. The temperature decreases as the lines are made thicker.