Dirac Fermions in condensed matter and beyond

TL;DR

This review discusses the theoretical aspects of Dirac points and fermions in two-dimensional systems, highlighting their manipulation, motion, and topological classification beyond graphene, with illustrative models.

Contribution

It provides a systematic theoretical framework for understanding Dirac points in various 2D systems, extending beyond graphene.

Findings

Systematic classification of Dirac point motions

Illustration of Dirac fermions in model systems

Insights into manipulation of Dirac points

Abstract

This review aims at a theoretical discussion of Dirac points in two-dimensional systems. Whereas Dirac points and Dirac fermions are prominent low-energy electrons in graphene (two-dimensional graphite), research on Dirac fermions in low-energy physics has spread beyond condensed-matter systems. In these alternative systems, a large versatility in the manipulation of the relevant band parameters can be achieved. This allows for a systematic study of the motion and different possible fusions of Dirac points, which are beyond the physical limits of graphene. We introduce the basic properties of Dirac fermions and the motion of Dirac points here and aim at a topological classification of these motions. The theoretical concepts are illustrated in particular model systems.