Coherent electron backscattering interference in non-uniform disordered systems

We study the coherent electron backscattering interference in the presence of electron dephasing in 2D/3D non-uniform (NU) disordered systems, within our virtual electron trap scattering (VETS) model, where the dephasing rate 1/τφ is taken to be due to the inelastic electron–electron or electron–phonon scattering. A possible saturation mechanism of apparent electronic dephasing is examined. The system considered is composed of two kinds of subsystems, namely, L-islands and H-region with contrasting diffusion constants, of which the L-islands (of low diffusion constant) act as virtual electron traps randomly dispersed in the percolating H-background (of high diffusion constant). The physics of VETS model is characterized by the two important dwell times, τf and τb, with τf/τb being the mean duration for which an electron wanders in the H-region/L-island before it leaves the region, respectively. In order to make connection with experiments, we introduce the notion of an effective system of uniform (U  ) disorder with a dephasing time τφ(effective)τφ(effective), which simulates in the aspect of backscattering the NU system being studied. The effective dephasing time τφ(effective)τφ(effective) thus introduced is a function of τφ, and the function, τφ(effective)τφ(effective)(τφ), is derived and examined. If τb⪢τf, an interesting phenomenon occurs in the range of temperature (T) where the true dephasing time τφ(T) lies between τf and τb, i.e., τf<τφ(T)<τb. In this case, we obtain τφ(effective)τφ(effective)(τφ)≈τf, which is insensitive to the variation in τφ (or T  ) and shows the signature of τφ(effective)τφ(effective) saturation. However, at the further lowered temperature where τφ(T)≥τb, τφ(effective)τφ(effective) rises up sharply without being saturated.