Multilayer silicene: structure, electronics, and mechanical property

TL;DR

This study uses first-principles calculations and molecular dynamics to explore the structure, electronic properties, and mechanical behavior of multilayer silicene with various stacking configurations.

Contribution

It provides detailed insights into the metastable structures, electronic bandgap, and mechanical properties of multilayer silicene, highlighting the effects of stacking and layer number.

Findings

Bilayer silicene exhibits a bandgap of 0.4419 eV.

Mechanical properties like fracture stress depend on stacking mode.

Multilayer silicene has a lower bending modulus than graphene.

Abstract

Herein, we performed first principle calculation and classical molecular dynamics simulation to study structural optimization, band structure, and mechanical properties of differently stacked multilayer silicene. Several local energy minima have been identified as metastable conformation with different stacking mode and layer number. Bandstructure of low buckled AA bilayer silicene optimized with SCAN+rvv10 presents semiconducting behavior with a bandgap of 0.4419ev. Young's modulus of multilayer silicene shows low dependency on layer number or stacking mode. Whereas, fracture stress and strain is sensitive to the number of layers, specific stacking mode, and chirality. Furthermore, bending modulus of multilayer silicene (e.g., 0.44ev for monolayer silicene) is even lower than that of graphene, which may attribute to the flexibility of bond angle.