Conductance of mesoscopic systems with magnetic impurities

[摘要] We investigate the combined effects of magnetic impurities and applied magnetic field on the interference contribution to the conductance of disordered metals. We show that in a metal with weak spin-orbit interaction, the polarization of impurity spins reduces the rate of electron phase relaxation, thus enhancing the weak-localization correction to conductivity. Magnetic field also suppresses thermal fluctuations of magnetic impurities, leading to a recovery of the conductance fluctuations. This recovery occurs regardless of the strength of the spin-orbit interaction. We calculate the magnitudes of the weak-localization correction and of the mesoscopic conductance fluctuations at an arbitrary level of the spin polarization induced by a magnetic field. Our analytical results for the h/e Aharonov-Bohm conductance oscillations in metal rings can be used to extract the spin and gyromagnetic factor of magnetic impurities from existing experimental data.

[关键词] SPIN-GLASSES;DISORDERED CONDUCTORS;WEAK LOCALIZATION;FLUCTUATIONS;MAGNETORESISTANCE;SCATTERING;METALS;WIRES;ELECTRONS;TRANSPORT