Non-Debye Behavior of Dynamic Conductivity - Relaxon Miniband and Conductivity in Superionic Conductor Superlattice -

Abstract

The relaxation mode (relaxon) theory is applied to a superionic conductor superlattice, which leads to minibands of relaxon eigenvalues E_q and a non-Debye dynamic conductivity σ (ω) therefrom. It is made clear that non-diffusive relaxons of zero wave number q = 0, made of extended and localized modes, give rise to the frequency exponent s in Reσ (ω)≈ σ₀ + Aω^s in two ways: especially for the extended modes, the square of a mode diffusion length is approximately of hyperbolic type 1/E_{q = 0}^a with non-integer exponent α, which results in s≈ 0.6. The localized mode, on the other hand, works for the other type of non-Debye behavior of s≈ 1.