Gibo et al., "Crossover from Efros-Shklovskii variable range hopping to nearest-neighbor hopping in silicon nanocrystal random network," Applied Physics Express, vol.
Kamimura, "Correlation effects on variable range hopping conduction and the magnetoresistance," Journal of the Physical Society of Japan, vol.
As the dopant concentration increases, the density of hopping sites increases making the variable range hopping
in the direction perpendicular to the polymer chains (enhancement of interchain charge transfer integral) resulting in the 3D hopping at higher dopant concentration.
Variable Range Hopping (VRH) Model ([T.sub.p] < T < [[theta].sub.D]/2).
While, in the high temperature regime (T > [T.sub.p]), the conduction can be explained by the variable range hopping (VRH) model and the small polaron hopping (SPH) mechanisms.
On a log-log scale, any of the variable range hopping theories would predict some bending of the data to the right of the straight line at low temperatures.
While no activation or variable range hopping fits are shown, it is clear from the figure that the temperature dependence of [R.sub.H] bears at least a qualitative resemblance to that of [R.sub.x] in Fig.