Insight of temperature and density-driven transition of sawtooth penta-silicene nanoribbons via molecular dynamics study

Abstract

The density-driven transitions of sawtooth penta-silicene nanoribbon (PSiNR) at different temperature points are investigated using classical Molecular Dynamics (MD). Under the confined z-boundary, we found that the penta-to-tetra and the liquid-to-tetra silicene transitions present a clear dependence on the temperature. Insights of the thermodynamics and structural properties such as ring size (RS) and coordination number (CN) distributions, radial distribution function, buckling, and interatomic distance have been carefully analyzed. Above the melting temperature, the liquid 2D silicene tends to direct aggregate from scattered low-membered ring domains into the tetra-silicene nanoribbon (TSiNR). Meanwhile, the transition in sawtooth penta-SiNR takes place from the boundary into the inner region. A phase diagram indicating a dependence on density and temperature is presented. On the other hand, without the confinement of the z-boundary, the sawtooth penta-SiNRs express the periodic rippling. High temperature and axial compressive strain also could induce the PSiNR roll into the nanotube. Our simulations provided insights into the structural variations involving both the density and temperature of sawtooth PSiNRs.