Molecular Dynamics Simulation of Two Dimensional Materials

Abstract

Ultra-thin materials like Graphene and Transition Metal dichalcogenides are a novel class of materials with robust applications in electronic devices. These 2D materials are one of the main driving forces behind the rise of nanotechnology. Therefore, researchers need to characterise such materials to find their suitable usage. These materials have multiple properties such as electronic, optical and mechanical. Mechanical properties such as elasticity, strength and plasticity define a material's usage. There are two common ways to investigate these materials. One such is Classical Mechanics, and the other is Density functional theory(DFT). This study focuses on the application of Molecular dynamics (MD) simulation to derive stress-strain relationships of such materials. LAMMPS is a tool that aids in performing the simulation. Interatomic potentials such as AIREBO and Stillinger-Weber potential are used to derive the required outcomes. The visual simulation results aid us in understanding and describing their fracture behaviour. In our work, we primarily focus on the temperature-dependent fracture to determine the ultimate tensile stress(UTS) of a material. Initially, we worked to examine the stress-strain relationship of armchair graphene monolayer due to varying temperatures from 300K to 2100K. Then, we thoroughly investigate molybdenum disulfide (MoS2) and molybdenum telluride (MoTe2) using the parameterised Stillinger-Weber potential. Finally, the fracture strength of MoTe2 is determined from 100K to 600K at an interval of 100K. The results for both armchair and zigzag are tabulated and plotted. We can observe that for each corresponding temperature, the armchair MoTe2 is stronger than zigzag MoTe2. Furthermore, we find that the young's modulus is unaffected due to the temperature change, which could help to determine the range and the application of the material in different field. Keywords: 2D mat