Nanocomposites and nanomaterials

Stochastic nature of failure of carbyne-graphene nanoelements under thermomechanical loading

Kotrechko Sergiy1,2,3, Gianfranco Palumbor4, Kolyvoshko Eugene1 , Luigi Tricarico4, Stetsenko Nataliya1 
1 G.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences of Ukraine, 36, Academician Vernadsky Blvd., Kyiv-03680, Ukraine.
E-mail: serkotr@gmail.com
2 National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” 37, Peremohy Ave. UA-03056 Kyiv, Ukraine
3 Taras Shevchenko Kyiv National University, 60, Volodymyrska Str., Kyiv-01601, Ukraine.
4 Politecnico di Bary, 4, E. Orabona Str.,Bari-70125, Italy.

Current trend of transition to practical use of nanoelements requires to study mechanisms that govern their lifetime under conditions of combined action of such factors as temperature and mechanical load. This is crucially important for straintronics elements, as they involve governing the functional properties of nanoelements by deforming them. Carbyne-graphene nanoelements (CGNs) are the most striking example of such nanoelements. They are graphene sheets connected by carbyne chains. Today they are considered as a key element of the all-carbon-based nanoelectronics of the future. When such nanoelements are stretched, the band gap changes significantly, so they can also be used, as the elements of nanoscale lasers and other optoelectronic devices with tunable wavelengths. 
This study ascertained an atomistic mechanism that governs stability and lifetime of such nanoelements under thermomechanical loading. Based on the findings of molecular dynamics simulation of CGNs' stretching in a wide temperature range, it is shown that their lifetime is governed by the waiting time for critical fluctuations in the lengths of contact bonds (CB), resulting in their failure. It is ascertained that mechanism of CB break is stochastic in nature. Within the framework of the fluctuation model of CB break developed earlier [1], a statistical law was obtained for the lifetime of CGNs under thermomechanical loading. It is exhibited that the stochasticity inherent in the CB break process gives rise to a significant scatter in the lifetime value. The standard deviation of lifetime is equal to its average value. This means that in the practical utilisation of CGNs, not the average value of lifetime should be used, but the lower scatter limit with a given value of the probability of its realization.
Based on the findings obtained, the temperature-force conditions are found under which the practical use of CGNs is possible.

1.	Kotrechko S., Timoshevskii A., Kolyvoshko E., Matviychuk Yu., and Stetsenko N. Thermomechanical stability of carbyne-based nanodevice // Nanoscale Res Lett. - 2017. - 12:327 P. 1-8.