Electron energy and phase relaxation on magnetic impurities

TL;DR

This paper investigates how magnetic impurities influence electron energy relaxation and phase coherence, revealing mechanisms that depend on magnetic field strength and providing results applicable to experimental observations in metallic wires.

Contribution

It introduces a detailed analysis of magnetic impurity effects on electron dephasing and energy exchange, including the impact of magnetic fields on these processes.

Findings

Magnetic impurities mediate energy exchange with a kernel proportional to 1/E^2.

Magnetic field suppresses energy exchange at energies below Zeeman energy.

Zeeman splitting reduces electron dephasing, affecting interference phenomena.

Abstract

We discuss the effect of magnetic impurities on the inelastic scattering and dephasing of electrons. Magnetic impurities mediate the energy exchange between electrons. This mechanism is especially effective at small energy transfers $E$ in the absence of Zeeman splitting, when the two-particle collision integral in the electron kinetic equation has a kernel $K\propto 1/E^2$ in a broad energy range. In a magnetic field, this mechanism is suppressed at $E$ below the Zeeman energy. Simultaneously, the Zeeman splitting of the impurity spin states reduces the electron dephasing rate, thus enhancing the effect of electron interference on conduction. We find the weak localization correction to the conductivity and the magnitude of the conductance fluctuations in the presence of magnetic field of arbitrary strength. Our results can be compared quantitatively with the experiments on energy relaxation in short metallic wires and on Aharonov-Bohm conductance oscillations in wire rings.