title: Origins of Dirac cones and parity dependent electronic structures of α-graphyne derivatives and silagraphynes.
abstract: Compared with graphene, graphyne and its derivatives possess more diversified atomic configurations and richer electronic structures including Dirac cones (DCs) and metallic features depending on the parity of the number of sp carbon atoms of graphynes. This report described conceptually the process of DC formation of α-graphyne within a tight-binding framework parameterized from density functional calculations. We propose a "triple coupling" mechanism elucidating the DC formation and some flat bands of α-graphynes where the couplings among the three sp carbon chain atoms are critical. The extension of this mechanism further explains the origins of DCs of silagraphynes and the parity dependent electronic structures of α-graphyne derivatives with extended sp carbon chains. Understanding these origins helps in tuning electronic properties in the design of C or C-Si based nanoelectronic devices.
authors.affiliation: Department of Materials Physics and Chemistry, School of Materials Science and Engineering, and Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, No. 3-11 Wenhua Road, Shenyang 110819, P. R. China. xwli@mail.neu.edu.cn and Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
authors.forename: Xuming
authors.initials: X
authors.lastname: Qin
authors.affiliation: Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China and Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China. yiliu@shu.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Materials Physics and Chemistry, School of Materials Science and Engineering, and Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, No. 3-11 Wenhua Road, Shenyang 110819, P. R. China. xwli@mail.neu.edu.cn and Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
authors.forename: Baoqian
authors.initials: B
authors.lastname: Chi
authors.affiliation: Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
authors.forename: Xinluo
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Materials Physics and Chemistry, School of Materials Science and Engineering, and Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, No. 3-11 Wenhua Road, Shenyang 110819, P. R. China. xwli@mail.neu.edu.cn.
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Li