A new model for ac conduction in disordered solids

Abstract

A new model based on a spatial electrical inhomogeneity of the material is presented to describe the ac conductivity of disordered solids. With the central assumption that both the dc and the ac conductivity are due to the same mechanism, the model calculation fits quantitatively the ac response against both temperature and frequency of some different amorphous solids. The analysis accentuates the difficulties and uncertainties which arise in deducing microscopic properties from ac conduction data. The model calculation suggests that at least in the high temperature regime processes working at the Fermi‐level do not determine the ac behaviour of disordered solids.

Dielectric relaxation and variable-range-hopping conduction in BaSn1−x Cr x O3 system

“…In the high temperature region (above 500 K) due to hopping of oxygen vacancies, V O . The observed activation energies for low and high temperature regions are in agreement with activation energy reported for hopping of electrons and V O in other perovskite oxides [18,29,34,[37][38][39].…”

“…(8) Even though σ o may vary many orders of magnitude the ac conductivity varies relatively little for different solids and different temperatures. Various models have been proposed for conduction behaviour of disordered solids among them is hopping model [34]. In this model one assume the presence of inhomogeneity on the atomic scale, by assuming randomly varying jump frequencies for charge carriers [33].…”