Anomalous Negative Magnetoresistance Caused by Non-Markovian Effects

摘要

A theory of recently discovered anomalous low-field magnetoresistance is developed for the system of two-dimensional electrons scattered by hard disks of radius a, randomly distributed with concentration n. For small magnetic fields the magentoresistance is found to be parabolic and inversely proportional to the gas parameter, δρ_(xx)/ρ ～ ― (ω_cτ)~2a~2. With increasing field the magnetoresistance becomes linear δρ_(xx)/ρ ～ ― ω_cτ in a good agreement with the experiment and numerical simulations.