The electric resistance and the transport properties of carbon nanotube with a Cu chain: A First-Principle study
- PDF / 876,349 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 103 Downloads / 133 Views
The electric resistance and the transport properties of carbon nanotube with a Cu chain: A First-Principle study Chengyu Yang and Quanfang Chen Mechanical and Aerospace Engineering Department, University of Central Florida, Orlando, Florida, 328162450, USA [email protected] ABSTRACT The electric resistance and the transport properties of a carbon nanotube (5,5) adsorbed with a copper chain connected with two copper end electrodes have been calculated by employing the nonequilibrium Green’s function and the Density Function Theory. The properties of the pure carbon nanotube (5,5) with the Cu electrodes have also been calculated as a reference. Both the equilibrium and the nonequilibrium conditions have been investigated. The results have shown that the electrical resistance of the metallic CNT (5,5) has been reduced by the adsorption of the Cu chain due to the interaction between the Cu and the CNT. The change of the I-V curve slope is also explained in terms of the transmission spectrum. 1. INTRODUCTION Metallic carbon nanotube (CNT) has been proven to be ballistic in transport with a large electron mean free path and a large current carrying capability. As a result, it has long been regarded as a potential replacement for Cu interconnects in nanoelectronics . However, due to the low density of states of CNTs near the Fermi level, a single carbon nanotube has a intrinsic resistance of about 6.5 k [1], which is greater than copper and could cause excessive RC delays of signals. On the other hand, bundles of carbon nanotubes, since the parallel channels contribute to the conduction, have been proposed and experimentally proved as a better candidate than the individual CNT [24]. However, it is difficult to utilize carbon nanotubes alone as the interconnects in the actual device [5]. Metals on the other hand, could provide carbon nanotubes' both the support and the link with their environment. Therefore metal/carbon nanotube hybrid systems would be a most important system in nanotechnology [6]. Titanium chain has been proved to change Carbon nanotube’s electronic structure and the conduction nature[7]. It has been reported that the incorporation of a titanium chain modifies the electronic structure of carbon nanotube via the charge transfer and the orbital hybridization[5, 8, 9]. In comparison to titanium, copper is also a transition metal with 3d electrons that could interact with carbon nanotubes. Our assumption is that Cu could generate delocalized states in utilizing carbon nanotube’s long mean free path, thus produce a potential higher electric conductance in the form of hybrid material. Instead of using the parallel channels in CNT bundles, free electrons from Cu contribute to CNT’s density of states (DOS) at the Fermi level. Therefore the Cu atoms may enhance the CNT’s conductance and provide a mechanical support and the electronic link to its environment at the same time. 2. CALCULATION AND SIMULATION MODEL In this article, we present the Cu chain’s effect on the transport properties and the electric conduct
Data Loading...
