Linker-Symmetry-ControlledCarrier Band Inversionin Triarylmethyl Radical (TAM)-Biphenylene Networks

2D carbon allotropes are receiving growing attention due to their unique electronic properties. Recently, unusual bipheneylene 2D networks (BPN), which were theoretically predicted to feature an intriguing flat band at the Fermi energy, have been successfully synthesized as 1D nanoribbons. In this study, we use density functional theory to explore BPN analogues constructed from six triarylmethyl radical (TAM) molecules linked by acetylene units. Our computational results show that the number of acetylene units in the linker has an effect of reversing the band dispersions of electrons and holes. Careful examinations of this phenomenon using tight-binding models and frontier orbital symmetries reveal that such linker-symmetry-controlled carrier band inversion is a universal effect in 2D networks with potential applications for modulating transport and switching behaviors.