Structural and Electronic Properties of Single-Walled Carbon Nanotube Heterojunctions*

Inspired by recent experiments[1], we present a systematic approach to construct structural models of mostly linear single walled carbon nanotube (SWCNT) heterojunctions. A minimum number of 5-7 defects is found to be required to join two SWCNTs of differing chiralities. Using nearest-neighbor tight-binding and first-principles density functional theory, we explore the sensitivity of the heterojunction electronic structure and transport properties to different arrangements of the interfacial 5-7 defects, and discuss their implications for future experiments and nanoelectronic applications. \begin{thebibliography}{1} \bibitem{bj} B. Chandra, J. Hone, {\it Unpublished}. \end{thebibliography}