Theoretical Study of the Mechanical Behavior of Individual TiS2 and MoS2 Nanotubes

Similar to carbon, several transition-metal chalcogenides are able to form tubular structures. Here, we present results from systematic theoretical investigations of structural and mechanical properties of MoS2 and TiS2 nanotubes in comparison to each other, to carbon nanotubes, and to corresponding experimental results. We have obtained the nanotube's Young's moduli (Y), Poisson ratios (v), and shear moduli (G) as functions of diameter and chirality, using a density-functional-based tight-binding method. Additionally, we have simulated tensile tests by Born-Oppenheimer molecular dynamics simulations. The influence of structural defects on the investigated mechanical properties has been studied as well. As a result of the simulated stretching experiments, we found that TiS2 nanotubes can be stretched only half as much as MoS2 nanotubes.