Dynamic-RKKY induced time-reversal symmetry breaking and chiral spin liquids

TL;DR

This paper investigates how dynamic RKKY interactions can induce time-reversal symmetry breaking and chiral spin liquids in Kondo lattice systems, revealing new ways to manipulate topological and chiral magnetic states.

Contribution

It introduces a dynamic RKKY framework that captures effects missed by static approximations, demonstrating the induction of spin chirality and topological features in Kondo lattices.

Findings

Dynamic RKKY interacts with external magnetic fields to induce spin chirality.

Chiral edge states and non-trivial topology are realized in honeycomb Kondo lattices.

External control can tune Dzyaloshinskii-Moriya interactions in centrosymmetric materials.

Abstract

We study the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in various Kondo lattice systems. We argue that the weak Kondo-coupling expansion contains certain physics which is lost in the usual static approximation to the spin susceptibility. Most notably, while the former is sensitive to the time-reversal symmetry breaking, the latter is blind to it. Using exact diagonalization on small systems, we show that this enables inducing spin chirality by an external magnetic field. To study larger systems, we use a large-N approximation to capture the effect of dynamic-RKKY interaction on U(1) spin liquids. On a honeycomb Kondo lattice with Haldane fluxes for electrons, we show that the non-trivial topology and chiral edge states are induced on the spinons. Our results suggest that dynamic RKKY in combination with external magnetic field or in proximity to topological electronic materials, can be used as a tunable Dzyaloshinskii-Moriya even in centrosymmetric materials.