Spin-lattice relaxation rate of a magnetic impurity in the spin degenerate Anderson model

TL;DR

This paper uses renormalization group methods to analyze the spin-lattice relaxation rate near a magnetic impurity in the Anderson model, revealing universal behavior and a peak at the Kondo temperature.

Contribution

It provides a detailed calculation of the relaxation rate in the Anderson model, highlighting universal scaling and the influence of impurity-probe distance.

Findings

Relaxation rate peaks at the Kondo temperature.

At low temperatures, the system behaves as a heavy Fermi liquid.

The relaxation rate scales universally with temperature and Kondo resonance width.

Abstract

The renormalization group formalism was applied to calculate the spin-lattice relaxation rate of a well-defined magnetic moment in the neighborhood of a spin degenerate Anderson impurity. In the Kondo regime, the spin-lattice relaxation rate as a function of the temperature presents a peak at the Kondo temperature; for temperature much lower then the Kondo temperature, the system behaves as a heavy Fermy liquid, with an enhanced density of states, which increases with the decreasing of the Kondo temperature; the product of the temperature by the relaxation rate remains an universal function of the temperature, which is scaled by the Kondo resonance width, up to temperatures of the order of one hundred of this width; for temperatures lower then the Kondo temperature, the spin-lattice relaxation rate is proportional to the magnetic susceptibility multiplied by the temperature; the peak of spin-lattice relaxation at the Kondo temperature decreases with the increasing of the distance between the Anderson impurity and the magnetic probe.