Rate theory of yield in boron nitride nanotubes

Combining ab initio computations with a probabilistic rate approach, we investigate the bond-rotation mode of plastic yield in boron nitride nanotubes to predict the kinetic and thermodynamic strength. Relative to carbon nanotubes, the boron nitride yield defects have lower activation but higher formation energies. This leads to an interesting phenomenon of strength crossover for these two important materials under different conditions: at moderate temperatures carbon is stronger, while at high temperatures (or extremely long times) the situation is reversed and boron nitride is more stable thermomechanically.