Optical conductivity of topological Kondo insulating states
  Using real-space dynamical mean field quantum Monte Carlo simulations, we study the optical conductivity of two-dimensional topological Kondo insulating states. We consider model parameters which allow us to consider mixed valence and local moment regimes. The real space resolution inherent to our approach reveals a renormalization of the hybridization gap as one approaches the edge. Low energy transport is dominated by the helical edge state and the corresponding Drude weight scales as the coherence scale of the heavy fermion state. The concomitant renormalization of the edge state velocity leads to a constant edge local density of states. We discuss the implication of our results for the three dimensional case. 
Kuang-Shing Chen and Jan Werner and Fakher Assaad
cond-mat.str-el