Nanocomposites and nanomaterials

Fluctuation model of instability and contact bond break in carbyne-graphene nanoelements
S. Kotrechko1, E. Kolyvoshko2, A. Timoshevskii1 N. Stetsenko1, 
 I. Mikhailovskij3
1 G.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences of Ukraine, Vernadsky Blvd.,36, Kyiv-03680, Ukraine.
E-mail: natusjaimp@gmail.com
2 Taras Shevchenko Kyiv National University, Volodymyrska Street, 64/13, Kyiv-01601, Ukraine.
3 Department of Low Temperatures and Condensed State, National Science Center, Kharkov Institute for Physics and Technology, National Academy of Sciences of Ukraine, Academicheskaja, 1, Kharkov 61108, Ukraine

Rapid development of nanotechnologies and beginning of the large scale use of nanoelements and nanodevices necessitated the problem of predicting their reliability and lifetime which is pre-determined by the thermo-mechanical stability of the contact bond between the carbyne and graphene. Specific feature of this problem is that the fluctuation-induced breaking of bonds occurs under the action of large force fields. In most cases these fields are induced by elastic deformations of the lattice, which provide an essential change in the functional properties – electrical and thermal conductivity, magnetic properties (this promising new direction of realising extraordinary functional properties of nanoelements was called «straintronics»). This doesn't enable the use of classical approaches to solve such problems, based on the theory of reactions.
The report addresses this problem by the example of modeling the failure of carbyne-graphene nanoelements (CGNs). Such CGN is two graphene sheets connected by a monatomic chain of carbon atoms. Based on the results of the DFT-calculations, atomic mechanism of CGNs' failure was analysed. Existence of a zone of the impossible equilibrium states of atoms (ZIES) is a characteristic feature of the atomism of breaking a contact bond in CGNs under conditions of a force field. The novel non-traditional model of the fluctuation-induced interatomic bond break in such conditions is offered. The existence of two mechanisms for CGN failure is predicted – high- and low-energy. The transition from the first to the second mechanism is manifested itself in decrease (by many orders of magnitude) in the lifetime of CGNs. The temperature ranges and mechanical load values are ascertained, at which the CGNs' lifetime is sufficient for their practical use.

1.	Timoshevskii A., Kotrechko S., and Matviychuk Yu. Atomic structure and mechanical properties of carbyne // Phys Rev.-2015.- 91 P. 245434 (9).
2.	Kotrechko S., Timoshevskii A., Kolyvoshko E., Matviychuk Y and Stetsenko N. Thermomechanical stability of carbyne-based nanodevice // Nanoscale Res Lett. -2017.- 12:327 P. 1-8.