Frustrated magnetism and resonating valence bond physics in two-dimensional kagome-like magnets

TL;DR

This paper investigates the complex magnetic phases of two-dimensional kagome-like antiferromagnets, revealing how varying exchange interactions lead to different frustrated and resonating valence bond states.

Contribution

It combines numerical, analytical, and RVB methods to analyze the phase diagram of kagome-like magnets with two inequivalent exchange couplings, highlighting new frustrated and valence bond crystal phases.

Findings

Identification of bipartite and heavily frustrated regimes

Discovery of low-lying singlet states as localized magnetic excitations

Stabilization of valence bond crystals with resonating structures

Abstract

We explore the phase diagram and the low-energy physics of three Heisenberg antiferromagnets which, like the kagome lattice, are networks of corner-sharing triangles but contain two sets of inequivalent short-distance resonance loops. We use a combination of exact diagonalization, analytical strong-coupling theories, and resonating valence bond approaches, and scan through the ratio of the two inequivalent exchange couplings. In one limit, the lattices effectively become bipartite, while at the opposite limit heavily frustrated nets emerge. In between, competing tunneling processes result in short-ranged spin correlations, a manifold of low-lying singlets (which can be understood as localized bound states of magnetic excitations), and the stabilization of valence bond crystals with resonating building blocks.