Zhu Jiajie, Schwingenschlögl Udo
PSE Division, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia.
ACS Appl Mater Interfaces. 2014 Jul 23;6(14):11675-81. doi: 10.1021/am502469m. Epub 2014 Jul 8.
Silicene is a monolayer of Si atoms in a two-dimensional honeycomb lattice, being expected to be compatible with current Si-based nanoelectronics. The behavior of silicene is strongly influenced by the substrate. In this context, its structural and electronic properties on MgX2 (X = Cl, Br, and I) have been investigated using first-principles calculations. Different locations of the Si atoms are found to be energetically degenerate because of the weak van der Waals interaction with the substrates. The Si buckling height is below 0.55 Å, which is close to the value of free-standing silicene (0.49 Å). Importantly, the Dirac cone of silicene is well preserved on MgX2 (located slightly above the Fermi level), and the band gaps induced by the substrate are less than 0.1 eV. Application of an external electric field and stacking can be used to increase the band gap.
硅烯是二维蜂窝晶格中的单层硅原子，有望与当前基于硅的纳米电子学兼容。硅烯的行为受到衬底的强烈影响。在此背景下，已使用第一性原理计算研究了其在MgX2（X = Cl、Br和I）上的结构和电子性质。由于与衬底的范德华相互作用较弱，发现硅原子的不同位置在能量上是简并的。硅的屈曲高度低于0.55 Å，接近自由站立硅烯的值（0.49 Å）。重要的是，硅烯的狄拉克锥在MgX2上保存良好（位于费米能级略上方），并且由衬底引起的带隙小于0.1 eV。施加外部电场和堆叠可用于增加带隙。
