Topological quantum materials from the viewpoint of chemistry

TL;DR

This review explores topological quantum materials from a chemistry perspective, highlighting classification methods, key ingredients, synthesis techniques, and physical characterization, emphasizing the interdisciplinary nature of topology in solid-state chemistry.

Contribution

It provides a comprehensive overview of topological concepts, synthesis, and characterization techniques tailored for chemists, connecting topology with chemical principles and materials science.

Findings

Classification of topological materials based on symmetry and band structure

Key ingredients include symmetry, inert pair effect, and spin-orbit coupling

Examples of topological materials and their physical properties

Abstract

Topology, a mathematical concept, has recently become a popular and truly transdisciplinary topic encompassing condensed matter physics, solid state chemistry, and materials science. Since there is a direct connection between real space, namely atoms, valence electrons, bonds and orbitals, and reciprocal space, namely bands and Fermi surfaces, via symmetry and topology, classifying topological materials within a single-particle picture is possible. Currently, most materials are classified as trivial insulators, semimetals and metals, or as topological insulators, Dirac and Weyl nodal-line semimetals, and topological metals. The key ingredients for topology are: certain symmetries, the inert pair effect of the outer electrons leading to inversion of the conduction and valence bands, and spin-orbit coupling. This review presents the topological concepts related to solids from the viewpoint of a solid-state chemist, summarizes techniques for growing single crystals, and describes basic physical property measurement techniques to characterize topological materials beyond their structure and provide examples of such materials. Finally, a brief outlook on the impact of topology in other areas of chemistry is provided at the end of the article.