Origin of Dirac Cones in SiC Silagraphene: A Combined Density Functional and Tight-Binding Study.
The formation of Dirac cones in electronic band structures via isomorphous transformation is demonstrated in 2D planar SiC sheets. Our combined density functional and tight-binding calculations show that 2D SiC featuring C-C and Si-Si atom pairs possesses Dirac cones (DCs), whereas an alternative arrangement of C and Si leads to a finite band gap. The origin of Dirac points is attributed to bare interactions between Si-Si bonding states (valence bands, VBs) and C-C antibonding states (conduction bands, CBs), while the VB-CB coupling opens up band gaps elsewhere. A mechanism of atom pair coupling is proposed, and the conditions required for DC formation are discussed, enabling one to design a class of 2D binary Dirac fermion systems on the basis of DF calculations solely for pure and alternative binary structures.
†Department of Physics and Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.|‡Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, No. 3-11, Wenhua Road, Shenyang 110819, P. R. China.
Xuming
X
Qin
†Department of Physics and Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.|§School of Materials Science and Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, P. R. China.
Yi
Y
Liu
‡Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, No. 3-11, Wenhua Road, Shenyang 110819, P. R. China.
Xiaowu
X
Li
§School of Materials Science and Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, P. R. China.
Jingcheng
J
Xu
‡Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, No. 3-11, Wenhua Road, Shenyang 110819, P. R. China.
Baoqian
B
Chi
†Department of Physics and Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
Dong
D
Zhai
†Department of Physics and Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
Xinluo
X
Zhao
2D silicon carbide; Dirac Fermi system; atom pairing; isomorphous transformation; nanosheet