Kagome metals

TL;DR

This review explores how kagome lattice structures in quantum materials can host novel electronic states resulting from the interplay of topology, frustration, and strong correlations, supported by recent experimental advances.

Contribution

It provides a comprehensive overview of the theoretical foundations and experimental progress in realizing new quantum phases in kagome lattice materials.

Findings

Kagome lattices enable unique electronic states due to their geometric frustration.

Recent experiments have realized novel quantum states in kagome materials.

Theoretical models explain the interplay of topology, frustration, and correlations in these systems.

Abstract

Three important driving forces for creating qualitatively new phases in quantum materials are the topology of the materials' electronic band structures, frustration in the electrons' motion or magnetic interactions, and strong correlations between their charge, spin, and orbital degrees of freedom. In very few material systems do all of these aspects come together to contribute on an equal footing to stabilize new electronic states with unprecedented properties; however the search for such systems can be guided by models of configurational motifs or key sublattices that can host such physics. One of the most fascinating structural motifs for realizing this rich interplay of frustration, electronic topology, and electron correlation effects is the kagome lattice. In this review, we provide an overview of the theoretical underpinnings driving the physics of kagome lattices, and we then discuss experimental progress in realizing novel states enabled by kagome networks in crystalline materials. Different material classes are discussed with an emphasis on the phenomenologies of their electronic states and how they map to interactions arising from their kagome lattices.