Carbon-rich carbon nitride monolayers with Dirac cones: Dumbbell C4N

• Published in: Carbon (New York) Vol. 118; pp. 285 - 290
• Main Authors: Li, Linyang, Kong, Xiangru, Leenaerts, Ortwin, Chen, Xin, Sanyal, Biplab, Peeters, François M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2017
• ISSN: 0008-6223; 1873-3891; 1873-3891
• DOI: 10.1016/j.carbon.2017.03.045

Two-dimensional (2D) carbon nitride materials play an important role in energy-harvesting, energy-storage and environmental applications. Recently, a new carbon nitride, 2D polyaniline (C3N) was proposed [PNAS 113 (2016) 7414–7419]. Based on the structure model of this C3N monolayer, we propose two new carbon nitride monolayers, named dumbbell (DB) C4N-I and C4N-II. Using first-principles calculations, we systematically study the structure, stability, and band structure of these two materials. In contrast to other carbon nitride monolayers, the orbital hybridization of the C/N atoms in the DB C4N monolayers is sp3. Remarkably, the band structures of the two DB C4N monolayers have a Dirac cone at the K point and their Fermi velocities (2.6/2.4 × 105 m/s) are comparable to that of graphene. This makes them promising materials for applications in high-speed electronic devices. Using a tight-binding model, we explain the origin of the Dirac cone. Dirac cone band structures of DB C4N monolayers and the corresponding electron wave functions at the Dirac cone. [Display omitted]