Optical conductivity associated with solitons in the Peierls state as   modified by zero-point-motion disorder
  We extend previous work to consider the effect of the soliton on the density of states and conductivity of quasi-one-dimensional Peierls systems with quantum lattice fluctuations, modeled by a random static disorder. Two features have been verified over an order of magnitude variation in the disorder. (1) The soliton density of states and the leading edges of both the soliton-to-band and the band-to-band conductivities have universal scaling forms. (2) The soliton-to-band conductivity has the remarkable feature that the leading edge is accurately predicted by the joint density of states while the trailing edge tracks the rigid-lattice conductivity. Or, in other words, disorder dominates the leading edge, while matrix element effects are predominant for the trailing edge. 
Kihong Kim and John W. Wilkins