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arXiv · 0802.3203

Magneto-spectroscopy of Highly-Aligned Carbon Nanotubes: Identifying the Role of Threading Magnetic Flux

J. Shaver·S. A. Crooker·J. A. Fagan·E. K. Hobbie·N. Ubrig·O. Portugall·V. Perebeinos·Ph. Avouris·J. Kono
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Abstract

We have investigated excitons in highly-aligned single-walled carbon nanotubes (SWCNTs) through optical spectroscopy at low temperature (1.5 K) and high magnetic fields ($\textbf{\textit{B}}$) up to 55 T. SWCNT/polyacrylic acid films were stretched, giving SWCNTs that are highly aligned along the direction of stretch ($\hat{n}$). Utilizing two well-defined measurement geometries, $\hat{n}\parallel\textbf{\textit{B}}$ and $\hat{n}\perp\textbf{\textit{B}}$, we provide unambiguous evidence that the photoluminescence energy and intensity are only sensitive to the $\textbf{\textit{B}}$-component parallel to the tube axis. A theoretical model of one-dimensional magneto-excitons, based on exchange-split `bright' and `dark' exciton bands with Aharonov-Bohm-phase-dependent energies, masses, and oscillator strengths, successfully reproduces our observations and allows determination of the splitting between the two bands as $\sim4.8$ meV for (6,5) SWCNTs.

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J. Shaver, S. A. Crooker, J. A. Fagan, E. K. Hobbie, N. Ubrig, O. Portugall, V. Perebeinos, Ph. Avouris, J. Kono. 2008-02-21. Magneto-spectroscopy of Highly-Aligned Carbon Nanotubes: Identifying the Role of Threading Magnetic Flux. https://doi.org/10.1103/physrevb.78.081402

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