S2P2C12: A two-dimensional anisotropic Janus material with tunable Dirac cone

Abstract

Based on first-principles calculations, we propose a two-dimensional anisotropic Janus material, S2P2C12, which can be obtained from doped graphene with S and P atoms. The cohesive energy of a S2P2C12 monolayer is as high as 6.11 eV/atom, which exceeds that of many experimentally existing two-dimensional materials and reflects its excellent stability. Electron band analyses demonstrate that the Janus S2P2C12 monolayer is a semimetal with a strongly anisotropic type-I Dirac cone, which is rare for two-dimensional materials of the Janus family. Such a Dirac cone survives in-plane strain and can be transformed into a type-III Dirac cone. Its high, direction-dependent Fermi velocity of over 105 m/s is indispensable for emerging high-speed flexible electronic devices.