Realizing Graphene-like Dirac Cones in Triangular Boron Sheets by Chemical Functionalization
The most important feature in graphene is its unique Dirac cone, which closely connects with many novel properties. However, this type of Dirac cones are rare and difficult to be realized in non-group Ⅳ two-dimensional (2D) materials. In this work, we have theoretically designed a family of triangular B3X (X = H, F, Cl) monolayers with graphene-like Dirac cones in terms of constituent atomic orbitals, as well as high thermal stability. Furthermore, based on the idea of effective charge transfer, we have uncovered the key mechanism for the realization of graphene-like Dirac cones with a concise bond distributions model, which is valid for the 2D boron based materials with single Dirac cone and double Dirac cones. Our results offer new insights into the design of 2D boron based Dirac semimetals by chemical adsorption, which may stimulate the development of 2D boron research.