First-Principles Analysis on pi-bonded Chain Structure on Several Polytypes of SiC Surfaces: Importance of Stacking Sequence on Energetics and Electronic Structures

摘要

Using first principles calculations based on a density functional theory, the energetics and electronic properties of a (2 x 1) pi-bonded chain structure in several polytypes of SiC surfaces are discussed with special attention to the stacking sequence of SiC bilayers. We found that the stacking sequence of the topmost two SiC bilayers plays a decisive role for the stability and electronic structures of the pi-bonded chain structure. We showed that the homo-elemental bonds in pi-bonded chain structures cause alterations in the electronic structures of both the Si-and C-faces. The energetics of pi-bonded chain structures on other group IV and IV-IV compound semiconductors were also investigated. We also showed that the buckling structure in the monolayer honeycomb lattice reflects the buckling of the topmost two atoms in the pi-bonded chain structure observed in Si(111) and Ge(111).