Quantum transport in long-range random magnetic fields Original Research Article

The frequency dependence of the ac conductivity for a two-dimensional electron system subject to a long-range random magnetic field (RMF) with zero mean is numerically investigated. It is found that the ac conductivity σ(ω) increases in the frequency regime lower than a crossover frequency ωc, and linearly decreases for ω⪢ωc. The crossover frequency is governed by the localization length of the electron eigenstate at the Fermi energy. These facts indicate that quantum-interference effects are crucial for ac transport in the long-range RMF in conflict with the recent analytical argument.