Overscreened Kondo fixed point in S=1 spin liquid

TL;DR

This paper explores a novel realization of the overscreened Kondo effect within a two-dimensional S=1 spin liquid containing a magnetic impurity, highlighting the interplay between gauge fields and non-Fermi-liquid behavior.

Contribution

It introduces a model of an S=1/2 impurity in an S=1 spin liquid with a Fermi surface, analyzing the effects of gauge fields on the overscreened Kondo fixed point using large-N and dynamical exponent expansions.

Findings

Gauge fields induce observable modifications in Kondo physics.

The overscreened Kondo fixed point exhibits weak but detectable changes due to gauge coupling.

Potential experimental signatures of gauge field effects in Kondo systems.

Abstract

We propose a possible realization of the overscreened Kondo impurity problem by a magnetic s=1/2 impurity embedded in a two-dimensional S=1 U(1) spin liquid with a Fermi surface. This problem contains an interesting interplay between non-Fermi-liquid behavior induced by a U(1) gauge field coupled to fermions and a non-Fermi-liquid fixed point in the overscreened Kondo problem. Using a large-N expansion together with an expansion in the dynamical exponent of the gauge field, we find that the coupling to the gauge field leads to weak but observable changes in the physical properties of the system at the overscreened Kondo fixed point. We discuss the extrapolation of this result to a physical case and argue that the realization of overscreened Kondo physics could lead to observations of effects due to gauge fields.