Structure and Properties of Dual-Ti-Doped Single-Walled Carbon Nanotubes Within Density Functional Theory

Abstract

Different types of substitution of one or two carbon atoms in (7, 7) single-walled carbon nanotube (SWCNT) by two Titanium atoms have been systemically studied within density functional theory based method. Fourteen different dual-Ti-doped SWCNT fragments were investigated and conformation IX doped with a Ti dimer is the most stable conformation. According to natural population and frontier molecular orbital analyses, the relative substitution positions of those two Ti atoms have significant impact on the local structure of doping site. Spin polarization occurs at the Ti atoms and such phenomenon helps to build new magnetic materials based on Ti-doped SWCNT. The special structure of the Ti-doped SWCNT with a C atom replaced by a Ti dimer in an insertion fashion brings about new properties to Ti-doped SWCNTs.