Spin Dynamics of Trimers on a Distorted Kagom\'e Lattice

TL;DR

This paper investigates the spin dynamics of trimers on a distorted Kagomé lattice, analyzing ground states, excitations, and neutron scattering, highlighting differences from standard spin-wave theory due to intra-trimer effects.

Contribution

It introduces a trimer-based approach to spin dynamics on a distorted Kagomé lattice, capturing intra-trimer zero point motion effects absent in standard spin-wave theory.

Findings

Trimer model matches experimental excitation spectra better at low energies.

Differences from standard spin-wave theory are due to intra-trimer zero point motion.

Application to real systems suggests improved understanding of Kagomé lattice materials.

Abstract

We treat the ground state, elementary excitations, and neutron scattering cross section for a system of trimers consisting of three tightly bound spins 1/2 on a distorted Kagom\'e lattice, subject to isotropic nearest neighbor (usually antiferromagnetic) Heisenberg interactions. The interactions between trimers are assumed to be weak compared to the intra trimer interactions. We compare the spin-wave excitation spectrum of trimers with that obtained from standard spin-wave theory and attribute the differences at low energy to the fact that the trimer formulation includes exactly the effects of intra-trimer zero point motion. Application to existing systems is briefly discussed.