Effects of Van der Waals Bonding on the Compressive Mechanical Behavior of Bulk Bi2Te3: A Molecular Dynamics Study

Abstract

Along the c axis of the crystal lattice, Bi2Te3 has periodic quintuple layers “ Te1 Bi Te2 Bi Te1–” which are connected by Van der Waals bonding. The weak bonding between Te1–Te1 layers substantially affects the mechanical properties of Bi2Te3. In the work discussed in this paper, the molecular dynamics method was used to study the mechanical properties of cuboid single-crystal of bulk Bi2Te3 under compressive loads. The emphasis was on the effects of the Van der Waals bonding on the deformation and failure mechanism. The molecular dynamics simulation results revealed that Van der Waals bonding has a dominant effect on the mechanism of deformation, and fundamentally determines the ultimate stress and fracture strain. Furthermore, the compressive load along the a and c axes lead to quite different failure behavior, which can be distinguished by their specific effects on the deformation of the Van der Waals bonding. However, only models with the load along the a axis dramatically demonstrate the effect of strain rate on the stress–strain curves, in accordance with the poor structural stability.