Abstract Submitted to the    CCTN09 Symposium:

Mechanical properties and quantum conductance of carbon nanocoils

Lizhao Liu, Haili Gao, Jijun Zhao

Dalian university of technology

liulizhaoalex@yahoo.com.cn

XXI. General Studies of Carbon Nanostructures

Since the discovery of carbon nanotube (CNT) in 1991, low-dimensional carbon nanostructures have attracted great attention due to their potential applications in nanoscale materials and devices. Carbon nanocoil (CNC) or coiled carbon nanotube is a kind of quasi one dimensional (1D) nanostructure, which is similar to CNT except for its helical structure in the whole. Compared to CNT, much less is known about CNC due to the complex geometry structure and difficulty in producing high-crystalline samples. Early theoretical studies were mainly focused on the atomic structure and stabilities, while the mechanical and transport properties of CNC is largely unclear from the theoretically side. In this work, we employed a recently developed tight-binding (TB) total energy model to investigate the structural, mechanical, and electronic properties of single-walled CNC.
Single-walled carbon nanocoils of hexagonal form were built by curling single-walled carbon nanotubes and periodically introducing pentagons and heptagons on the corners. The equilibrium lattice constant and atomic structures of a series of nanocoils were optimized using TB calculations and their Young’s modulus can be obtained. 1D electronic band structures were also computed within the TB model. Comparative density functional calculations on smaller nanocoil show the validity of the TB results. The quantum conductance of the carbon nanocoils under compression or elongation was then calculated using a π-orbital tight-binding model incorporated with the non-equilibrium Green’s function theory. The correlation between quantum conductance, atomic structure, and mechanical deformation of the CNCs will be discussed. Our theoretical results suggest that carbon nanocoils could be a promising candidate for future nanoelectronics and NEMS devices.

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