13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- For small strains, both sides of nanoribbon shrink to release the deformation energy, and no structural defects appear at this stage. For larger strains, bond breakage in the edge is observed and spreads toward the center as the strain increases. With the strain increasing further more, we find that sliding happens, and many atoms rearrange in the neck region. The deformation mechanism of a shearing action is similar to that of silicon nanowire [29]. After the formation of the neck, the plastic deformations have been carried mainly through the reconstruction and rearrangement of the neck reion. Beyond this region, the nanoribbon keeps ordered structure and have no significant change. Despite that the EDIP model gives a considerably accurate Young’s modulus of bulk silicene, a detailed analysis of the fracture behavior of silicene nanoribbons is still needed with different empirical potentials or ab initio calculations. 4. Conclusions In this paper, the chirality and size effects on the mechanical properties of silicene nanoribbons are investigated based on atomistic simulation. Compared with the ab initio calculations, EDIP model of bulk silicene gives a more accurate Young’s modulus than other empirical potentials. As for bulk silicene, uniaxial tensile test along the zigzag direction has a larger critical strain and stress compared to the armchair direction. The Young’s modulus increases as the size of silicene nanoribbons increases. Significant slip activities are observed in MD simulations with EDIP model. Further theoretical and experimental studies are needed to study the mechanical properties of this new 2D silicon nanomaterial. Acknowledgements The work is supported by China Postdoctoral Science Foundation, and Fundamental Research Funds for the Central Universities under Grant No.HIT.NSRIF.2013031. References [1] C. Lee, X. Wei, J. W. Kysar, and J. Hone, Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene. Science 321 (2008) 385. [2] C. A. Marianetti and H. G. Yevick, Failure Mechanisms of Graphene under Tension. Phys. Rev. Lett. 105 (2010) 245502. [3] K. S. Novoselov, A. K. Geim, S. V. Morozov, et al., Thin Carbon Films. Science 306 (2004) 666. [4] A. H. Castro Neto, F. Guinea, N. M. R. Peres, K. S. Novoselov, and A. K. Geim, The electronic properties of graphene. Reviews of Modern Physics 81 (2009) 109. [5] C. Soldano, A. Mahmood, and E. Dujardin, Production, properties and potential of graphene. Carbon 48 (2010) 2127-2150. [6] J. Kang, F. Wu, J. Li, Symmetry-dependent transport properties and magnetoresistance in zigzag silicene nanoribbons. Appl. Phys. Lett. 100 (2012) 233122. [7] S. Lebegue, O. Topsakal, Electronic structure of two-dimensional crystals from ab initio theory. Phys. Rev. B 79 (2009) 115409. [8] R. Qin, C. Wang, W. Zhu, Y. Zhang, First-principles calculations of mechanical and electronic properties of silicene under strain. AIP ADVANCES, 2 (2012) 022159. [9] C. Leandri, H. Saifi, O. Guillermet, B. Aufray, Silicon thin films deposited on Ag(001): growth and temperature behavior. App. Surf. Sci. 177 (2001) 303. [10] P. D. Padova, C. Quaresima, C. Ottaviani, et al., Evidence of graphene-like electronic signature in silicene nanoribbons. Appl. Phys. Lett. 96 (2010) 261905. [11] C. Lin, R. Arafune, K. Kawahara, et al., Structure of Silicene Grown on Ag(111). Applied Physics Express 5 (2012) 045802. [12] S. Cahangirov, M. Topsakal, E. Akturk, H. Sahin, S. Ciraci, Two- and One-Dimensional Honeycomb Structures of Silicon and Germanium. Phys. Rev. Lett. 102 (2009) 236804. [13] Z. Ni, Q. Liu, K. Tang, et al., Tunable Bandgap in Silicene and Germanene. Nano lett. 12 (2012) 113. [14] N. D. Drummond, V. Zolyomi, V. I. Fal’ko, Electrically tunable band gap in silicene. Phys. Rev. B 85 (2012) 075423.
RkJQdWJsaXNoZXIy MjM0NDE=