Silicene on Ag Substrate

Abstract

The isolation of graphene sheets from its parent crystal graphite has given the kick to experimental research on its prototypical 2D elemental cousin, silicene (Brumfiel 2013). Unlike graphene, silicene lacks a layered parent material from which it could be derived by exfoliation, as mentioned in Chap. 2. Hence, the efforts of making the silicene dream a reality were focused on epitaxial growth of silicene on substrates. The first synthesis of epitaxial silicene on silver (111) (Vogt et al. 2012; Lin et al. 2012) and zirconium diboride templates (Fleurence et al. 2012) and next on an iridium (111) surface (Meng et al. 2013), has boosted research on other elemental group IV graphene-like materials, namely, germanene and stanene (Matthes et al. 2013; Xu et al. 2013). The boom is motivated by several new possibilities envisaged for future electronics, typically because of the anticipated very high mobilities for silicene and germanene (Ye et al. 2014), as well as potential optical applications (Matthes et al. 2013). It is also fuelled by their predicted robust 2D topological insulator characters (Liu et al. 2011; Ezawa 2012) and potential high temperature superconductor character (Chen et al. 2013; Zhang et al. 2015). One of the most promising candidates as a substrate is Ag because from the studies of the reverse system, where Ag atoms were deposited on silicon substrate, it was known that Ag and silicon make sharp interfaces without making silicide compounds (Le Lay 1983). Indeed, studies on synthesis and characterization of silicene is mainly focused on using Ag(111) as substrates and hence we think it is important to understand this particular system. In this chapter, we present the experimental and theoretical studies investigating the atomic and electronic structure of silicene on Ag substrates.