Mechanics of Materials Creation: Nanotubes, Graphene, Carbyne, Borophenes

Abstract

In this article, we provide brief overview of how mechanics and computations play a role in understanding materials growth, creating new low-dimensional materials and exploring structural defects. First, we introduce a concept of screw dislocation for describing carbon nanotube growth and derive a kinetic relationship between growth rate and chiral angle. Deeper analysis of the subtle balance between the kinetic and thermodynamic views reveals sharply peaked distribution of near-armchair nanotubes, explaining puzzling (n, n-1) types observed experimentally. A combination of ab initio calculations and Monte Carlo models further explains the low symmetry shapes of graphene on substrates. Being monoatomic chains of carbon, carbynes are shown to be strong yet flexible, and undergo metal-semiconductor transition under tension, offering promising innovations for future nanotechnology. We then reveal how metal substrates could facilitate the formation of boron monolayers whose bulk counterparts are non-layered and lower in energy. Further remarks are given to High Burger's vector graphene defects called D-loops and interfaces in hybrid graphene-BN materials, both with significant out-of plane distortion and impact on the mechanical properties. All of these computationally modeled systems have significant implications for the future use of these nanomaterials.