p6 - Chiral Resonating Valence Bonds in the Kagome Antiferromagnet

TL;DR

This paper investigates the Kagome antiferromagnet, revealing a chiral spin liquid state with p6 symmetry breaking, supported by effective Hamiltonian modeling and spectral degeneracy analysis, with implications for experimental phonon observations.

Contribution

It introduces a new effective Hamiltonian approach that uncovers chiral symmetry breaking in the Kagome antiferromagnet, a novel finding in this context.

Findings

Identification of a spin liquid ground state without magnetic order.

Discovery of p6 chiral symmetry breaking through spectral degeneracies.

Prediction of optical phonon splitting due to chiral order parameter.

Abstract

The Kagome Heisenberg antiferromagnet is mapped onto an effective Hamiltonian on the star superlattice by Contractor Renormalization. Comparison of ground state energies on large lattices to Density Matrix Renormalization Group justifies truncation of effective interactions at range 3. Within our accuracy, magnetic and translational symmetries are not broken (i.e. a spin liquid ground state). However, we discover doublet spectral degeneracies which signal the onset of p6 - chirality symmetry breaking. This is understood by simple mean field analysis. Experimentally, the p6 chiral order parameter should split the optical phonons degeneracy near the zone center. Addition of weak next to nearest neighbor coupling is discussed.