Shape-memory alloys (SMAs) are a rare class of metal compound that after a huge mechanical strain can, on heating, recover their original atomic configuration. In the many useful applications of SMAs, the most studied material is NiTi (nitinol). The understanding on the NiTi properties in nano-scale calculations is still lacking. Here, we present a first-principles […]
Good cyclability is essential for the potential application of cathode materials. Here, we investigate the structural stability of two-dimensional (2D) Li-layered and three-dimensional (3D) structured polymorphs of Li2FeSiO4 and Li2MnSiO4 using the density functional theory calculation. We find that all 2D Li-layered polymorphs of both materials are unstable upon full-delithiation owing to layer exfolilation, which […]
Nanowires, both metallic and semiconducting, will be utilized for various NEMS applications, including mass, force and pressure sensing, next generation wireless applications, etc. One key issue for nanowire-based NEMS is that their Q-factors, due to surface effects degrade considerably with decreasing nanowire size. We have recently demonstrated using classical molecular dynamics that mechanical strain […]
Besides edge effects, graphene nanoresonators are expected to lose energy through interlayer friction effects, and the quality of attachment through van der Waal’s forces to the underlying (model silicon) substrate. We have quantified these losses as compared to an ideal graphene monolayer, as seen below. The key result is that, if intrinsic interlayer friction and […]
Interestingly, the study also found that the free edges of the graphene sheet often had the largest vibrational amplitudes during resonance. To verify this, finite element simulations of the graphene sheet were performed; by introducing non-uniform stresses in the suspended graphene sheet through application of both an in-plane stretch and an in-plane rotation, the authors […]