Unveiling the structure and interactions of silicene grown on MoS2: insights from hybrid molecular dynamics simulations.

Abstract

The interaction of silicene with MoS₂ surfaces has an important role in determining many properties of these systems. However, the intricate nature of silicene-based systems presents significant challenges for both experimental and computational investigations, often resulting in conflicting reports in the literature. Using molecular dynamics simulations with hybrid potentials, this work investigates the epitaxial growth of silicene on an MoS₂ substrate using a vapor-deposition-like method. The findings reveal that silicene can achieve stability on an MoS₂ substrate in an AB low-buckled configuration when both van der Waals and covalent interactions are considered. In this configuration, the silicene layer exhibits numerous defects, which can be significantly reduced by increasing the substrate temperature. In contrast, when only van der Waals interactions are accounted for, the system becomes unstable, leading to the collapse of the silicene structure into a three-dimensional disordered arrangement of Si atoms. A similar instability is observed in a heterostructure where a silicene sheet is intercalated between two MoS₂ layers. These results, combined with the lattice mismatch observed between silicene and MoS₂, suggest that van der Waals interactions alone are insufficient to ensure the mechanical stability of silicene.