Adsorption of heavy-element monolayers of Tl, Pb, and Bi at silicene: A DFT study

Abstract

This report investigates the adsorption of monolayers of X (Tl, Pb, Bi) at silicene and the dynamical stability of the system. Based on the density functional theory calculations it is shown that, X atoms bond strongly with the substrate giving rise to new X–Si hybrid states, which results in preferred surface configurations of X@silicene. Born-Oppenheimer quantum dynamics of the favorable structures were carried out at set temperature of 200 and 500 K for X@silicene supported on MoS2. The simulations predict that, the 1 × 1 phases of Tl, and Bi are dynamical stable at 200 K, while at 500 K the adsorbed atoms group in 3- or 4-atom patterns suggesting a possible 3×3 reconstruction. In contrast, Pb@silicene–1 × 1 is still predicted stable at 500 K. All structures exhibit a giant spin splitting (GSS) present in the metallic bands, which shows that, a heavy-element adsorption can be an effective method for giving rise to GSS at surfaces of 2D materials with no intrinsic spin splitting.