Chiral Spin Liquids in Arrays of Spin Chains

TL;DR

This paper presents a coupled-chain approach to model chiral spin liquids in two-dimensional systems, capturing their universal properties and suggesting easier stabilization in frustrated lattices like the kagome lattice.

Contribution

It introduces a novel coupled-chain construction for chiral spin liquids that incorporates their topological and edge state properties, extending previous models.

Findings

The approach accurately describes the low-energy physics of a solvable model.

Chiral spin liquids are more easily stabilized in frustrated lattices such as the kagome lattice.

The theory captures universal properties like edge states and ground state degeneracy.

Abstract

We describe a coupled-chain construction for chiral spin liquids in two-dimensional spin systems. Starting from a one-dimensional zigzag spin chain and imposing SU(2) symmetry in the framework of non-Abelian bosonization, we first show that our approach faithfully describes the low-energy physics of an exactly solvable model with a three-spin interaction. Generalizing the construction to the two-dimensional case, we obtain a theory that incorporates the universal properties of the chiral spin liquid predicted by Kalmeyer and Laughlin: charge-neutral edge states, gapped spin-1/2 bulk excitations, and ground state degeneracy on the torus signalling the topological order of this quantum state. In addition, we show that the chiral spin liquid phase is more easily stabilized in frustrated lattices containing corner-sharing triangles, such as the extended kagome lattice, than in the triangular lattice. Our field theoretical approach invites generalizations to more exotic chiral spin liquids and may be used to assess the existence of the chiral spin liquid as the ground state of specific lattice systems.