151 TITANIUM COVERAGE ON A SINGLE–WALL CARBON NANOTUBE: MOLECULAR DYNAMICS SIMULATIONS H. Oymak and S. Erkoc Department of Physics, Middle East Technical University, Ankara 06531 Turkey Abstract: The minimum energy structures of titanium covered finite-length C(8,0) singlewall carbon nanotubes (SWNT) have been investigated. We first parameterized an empirical potential energy function (PEF) for the CTi system. The PEF used in the calculations includes two- and three-body atomic interactions. Then, performing molecular dynamics simulations, we obtained the minimum-energy configurations for titanium covered SWNTs. The reported configurations include low and high coverage of Ti on SWNTs. We saw that one layer of Ti did not distort the nanotube significantly, whereas two-layer coverage showed an interesting feature: the second layer of Ti pushed the first layer inside the wall, but the general shape of the nanotube was not affected so much. Key words: nanotubes; molecular-dynamics; emprical potentials. 1. INTRODUCTION Carbon nanotubes are ideal for investigating molecular scale wires. Especially stable metal wires with diameters of the order of nanometers are indispensable in the development of nanoelectronics and nanodevice technologies [1]. In order to explore the intrinsic electrical properties of nanotubes and to obtain functional electronic devices with desired characteristics, low resistance metal-tube ohmic contacts are vital [2]. Several studies [3,4] revealed that low resistance metal-tube ohmic contacts could be achieved with Ti, Nb, and Ni metals. It was reported that the resistance of a Ti contacted metallic single-wall carbon nanotube (SWNT) was the lowest (as low as 12 kΩ) measured with individual SWNTs among all reported results [2,4]. A continuous Ti coverage of varying thicknesses, and quasi continuous coverage of Ni and Pd were obtained using electron-beam evaporation techniques [2,5]. It was pointed out by several researchers that the coverage of any metal on a SWNT could be mediated by first depositing titanium as a buffer layer [2,5,6]. It follows that a deep understanding of metal-tube