Thermodynamics of yield in boron nitride nanotubes

We investigate the atomistic mechanism of yield to mechanical tension in boron nitride nanotubes. The formation energy of the first emerging defect is computed by accurate ab initio calculations. Its susceptibilities to mechanical tension is further evaluated in an economical fashion, when only load-free clusters need to be considered. The obtained thermodynamic threshold is above that of the homologuous carbon system, whose exceptional resistance to mechanical yield is already recognized.