# Microscopic mechanism for higher-spin Kitaev model

## TL;DR

This paper develops a microscopic theory for the S=1 Kitaev model in two-dimensional systems, revealing conditions for spin liquid phases and proposing candidate materials, thus extending the understanding of higher-spin quantum spin liquids.

## Contribution

The paper derives a microscopic mechanism for realizing the S=1 Kitaev interaction in solid-state materials, connecting strong spin-orbit coupling and Hund's coupling to emergent spin liquid behavior.

## Key findings

- S=1 Kitaev interaction can be derived from superexchange in edge-shared octahedral systems.
- A finite regime of S=1 spin liquid exists with Heisenberg interactions included.
- Candidate materials and generalization to higher spins are discussed.

## Abstract

The spin S=$\frac{1}{2}$ Kitaev honeycomb model has attracted significant attention, since emerging candidate materials have provided a playground to test non-Abelian anyons. The Kitaev model with higher spins has also been theoretically studied, as it may offer another path to a quantum spin liquid. However, a microscopic route to achieve higher spin Kitaev models in solid state materials has not been rigorously derived. Here we present a theory of the spin S=1 Kitaev interaction in two-dimensional edge-shared octahedral systems. Essential ingredients are strong spin-orbit coupling in anions and strong Hund's coupling in transition metal cations. The S=1 Kitaev and ferromagnetic Heisenberg interactions are generated from superexchange paths. Taking into account the antiferromagnetic Heisenberg term from direct-exchange paths, the Kitaev interaction dominates the physics of S=1 system. Using exact diagonalization technique, we show a finite regime of S=1 spin liquid in the presence of the Heisenberg interaction. Candidate materials are proposed, and generalization to higher spins is discussed.