Conductivity peaks broadening in the quantum Hall regime

Abstract

We argue that it is the hopping transport that is responsible for broadening of the σ xx peaks. Explicit expressions for the width Δν of a peak as a function of the temperature T, current J and frequency ω are found. It is shown that Δν grows with T as ( T/ T 1) κ, where κ is the inverse localization-length exponent. The current J is shown to act like the effective temperature T eff(J) ∝ J 1 2 if T eff(J) ▪T . Broadening of the ohmic ac-conductivity peaks with frequency ω is found to be determined by the effective temperature T eff(ω)∼ h ̵ ω.