Effect of Point and Line Defects on the Mechanical Behavior of Single Layer MoTe2

Abstract

Following the groundbreaking discovery of graphene, the scientific community has witnessed a surge of interest in two-dimensional (2D) materials during recent times, remarkable capabilities and versatility for technological applications. Apart from graphene, a lot of promising work has been reported from other two-dimensional materials, including boron nitrides (like hBN, or "white graphite"), dichalcogenides (like MoS2), silicene, germanane, stanene, etc. To use these materials successfully in nanodevices and systems, it is important to figure out their elastic and mechanical properties. This will help define the limits of useful applications for flexible electronics. Two typical computational techniques for atomically thin models like 2D materials are molecular dynamics and density functional theory. Using the concepts of classical mechanics, molecular dynamics mimics the motion of atoms and molecules in a complicated system. In this study, the effect of point and line defects on the 2D transition metal dichalcogenides (TMDs) namely molybdenum ditelluride (MoTe2) were investigated using the Sandia National Laboratory's Molecular Dynamics Program LAMMPS. Three distinct types of point defect structures were investigated: a 2-tellurium vacancy structure, a 4-tellurium vacancy structure, and a 6-tellurium vacancy accompanied by a 1-molybdenum vacancy structure. Line defects were placed along armchair axis and zigzag axis. We characterized their mechanical characteristics, including axial stiffness, ultimate strength, and ultimate strain, as well as their thermal behavior at temperatures ranging from 1 Kelvin to 600 Kelvin, using atomistic computational techniques