Non-adiabatic small-polaron hopping conduction in SrTiO3-doped 90V2O5-10Bi2O3 glassy semiconductors

TLDR: In this paper, the percolation model of Triberis and Friedman applied to the small-polaron hopping regime is found to be consistent with the conductivity data.

Abstract: Dc electrical conductivities [sgrave]dc of 90V2O5−10Bi2O3 (VB) glasses doped with different SrTiO3 concentrations (0–40 wt%) are reported between 80 and 450 K. At higher temperatures, the Mott model of phonon-assisted small-polaron hopping between nearest neighbours is consistent with the conductivity data while, at low temperatures, the variable-range hopping model is found to be appropriate. The Holstein model indicates that, in the high-temperature regime, hopping occurs by a non-adiabatic process in contrast with the vanadate (VB) glasses. The percolation model of Triberis and Friedman applied to the small-polaron hopping regime is found to be consistent with the conductivity data. However, the consistency of the low-temperature conductivity data with the prediction of different theoretical models cannot be easily distinguished for these glasses. The estimated model parameters such as density of states, localization length and carrier mobility are found to be consistent with the formation of ...