Weakly frequency-dependent electrical conductivity in a chalcogenide glass

We report the observation in a chalcogenide glass of a weakly frequency-dependent electrical conductivity obeying the usual empirical relation σ' (ω) ∝ωⁿ but with a much lower than normal value of the exponent n, in the range 0.1–0.25 instead of 0.6–1.0. We suggest that this behaviour may be more common than is normally appreciated and that it has implications for the theoretical interpretation of both the alternating and the direct current conductivity. A new technique of logarithmic complex impedance diagrams is also introduced to facilitate the analysis of data.