Abstract Submitted for the MAR08 Meeting of The American Physical Society Excitons in Single-Walled Carbon Nanotubes in Different Local Environments: Effects of Strain and Disorder on Magnetic Brightening1

Submitted for the MAR08 Meeting of The American Physical Society Excitons in Single-Walled Carbon Nanotubes in Different Local Environments: Effects of Strain and Disorder on Magnetic Brightening1 T.A. SEARLES, ECE Dept, Rice University, D.J. HILTON, J. SHAVER, W.D. RICE, Rice Univ., Y.-D. JHO, GIST, Korea, S.A. MCGILL, NHMFL, J.A. FAGAN, E.K. HOBBIE, NIST, J. KONO, ECE Dept, Rice University — Recent experiments on single-walled carbon nanotubes (SWNTs) have shown that in the presence of a high magnetic field the two lowest-energy spin-singlet exciton states become bright [1]. Furthermore, this “magnetic brightening”, or increase in photoluminescence (PL) intensity as a function of magnetic flux through each SWNT, increases as the temperature decreases. Here, we report results of temperature-dependent magnetoPL from 2 to 200 K and up to 45 T on SWNTs of the same stock solution suspended in four different local environments. We compared both the brightening and temperature dependence of tubes stretch aligned and unaligned in poly-acrylic acid matrices. As expected, the tubes aligned at high magnetic field exhibited more brightening than those unaligned. We also investigated the behavior of SWNTs in two other matrices, iota-Carrageenan and gelatin. Along with the expected peak shifting and broadening from the effects of strain, we found that the temperature dependence changes with local environment. [1] S. Zaric et al., PRL 96, 016406 (2006); J. Shaver et al., Nano Lett. 7, 1851 (2007); I. B. Mortimer and R. J. Nicholas, PRL 98, 027404 (2007). 1We would like to acknowedge support from the Welch Foundation, NSF No. DMR0084173, the State of Florida, and DOE. T. A. Searles would like to thank the ONR/HBEC FEFF Fellowship Program. Thomas A. Searles Rice University Date submitted: 04 Dec 2007 Electronic form version 1.4