Theoretical studies of two-dimensional structure design and topological electronic properties of organic Dirac materials

Owing to the significant development in graphene, an increasing number of studies have been conducted to identify novel two-dimensional (2D) organic materials with Dirac cones and topological properties. Although a series of toy models based on specific lattice patterns has been proposed and demonstrated to possess a Dirac cone, realistic materials corresponding to the lattice models must be identified to achieve excellent properties for practical applications. To understand factors contributing to the rarity of 2D organic Dirac materials and provide guidance for identifying novel organic Dirac systems, we review recent theoretical studies pertaining to various 2D Dirac models and their corresponding organic Dirac materials, including the Haldane, Kagome, Libe, line-centered honeycomb, and Cairo pentagonal models. Subsequently, the corresponding structural and topological electronic properties are summarized. Additionally, we investigate the relationship between the existence of Dirac cones and their structural features, as well as the manner by which Dirac points emerge and propagate in these systems.