Due to their tubular nature, single-walled carbon nanotubes (SWNTs) exhibit nonintuitive quantum phenomena when subjected to a parallel magnetic field, which breaks time reversal symmetry and adds an Aharonov-Bohm phase to the electronic wavefunction. Our recent magneto-optical experiments on semiconducting SWNTs demonstrated that such a symmetry-breaking magnetic field can dramatically "brighten" an optically-inactive, or dark, exciton state at low temperature. We showed that this phenomenon, magnetic brightening, can be understood as a consequence of interplay between the strong intervalley Coulomb mixing and field-induced lifting of valley degeneracy. Furthermore, our magneto-optical experiments on metallic SWNTs revealed extremely large magnetic susceptibility anisotropy.

See our recent presentation for more details about magneto-optical properties of SWNTs: "Excitons in Carbon Nanotubes with Broken Time-Reversal Symmetry" (Colloquium, Department of Physics and Astronomy, Iowa State University, February 1, 2010).

Review Articles:

J. Kono, R. J. Nicholas, and S. Roche, "High Magnetic Field Phenomena in Carbon Nanotubes," in: Carbon Nanotubes, eds. A. Jorio et al. (Springer, 2008), pp. 393-421. (full text)

J. Shaver and J. Kono, "Temperature-Dependent Magneto-Photoluminescence Spectroscopy of Carbon Nanotubes: Evidence for Dark Excitons," Laser & Photon. Rev. 1, 260 (2007). (full text)

J. Kono et al., "Optical Processes in Single-Walled Carbon Nanotubes Threaded by a Magnetic Flux," in: Proc. of the 8 th Int. Symp. on Foundations of Quantum Mechanics in the Light of New Technology, eds. S. Ishioka and K. Fujikawa (World Scientific, 2006), pp. 234-241. (full text)

J. Kono and S. Roche, "Magnetic Properties," in: Carbon Nanotubes: Properties and Applications, edited by M. J. O'Connell (CRC Press, Taylor & Francis Group, 2006), Chapter 5, pp. 119-151. (full text)

J. Kono, "The Aharonov-Bohm Effect in Carbon Nanotubes" (in Japanese), Parity 21 (2006), pp. 46-49. (full text)

Regular Journal Articles:

T. A. Searles et al., "Large Anisotropy in the Magnetic Susceptibility of Metallic Carbon Nanotubes," Phys. Rev. Lett. 105, 017403 (2010). (abstract, full text, news)

J. Shaver et al., "Alignment Dynamics of Carbon Nanotubes in Pulsed Ultrahigh Magnetic Fields," ACS Nano 3, 131 (2009). (abstract, full text)

A. Srivastava et al., "Direct Observation of Dark Excitons in Individual Carbon Nanotubes: Inhomogeneity in the Exchange Splitting," Phys. Rev. Lett.101, 087402 (2008). (abstract, full text)

J. Shaver et al., "Magneto-optical Spectroscopy of Highly-Aligned Carbon Nanotubes: Identifying the Role of Threading Magnetic Flux," Phys. Rev. B 78, 081402(R) (2008). (abstract, full text)

J. Shaver et al., "Magnetic Brightening of Carbon Nanotube Photoluminescence through Symmetry Breaking," Nano Lett. 7, 1851 (2007). (abstract, full text)

S. Zaric et al., "Excitons in Carbon Nanotubes with Broken Time-Reversal Symmetry," Phys. Rev. Lett. 96, 016406 (2006). (abstract, full text, news)

S. Zaric et al., "Estimation of Magnetic Susceptibility Anisotropy of Carbon Nanotubes Using Magneto-Photoluminescence," Nano Lett. 4, 2219 (2004). (abstract, full text)

S. Zaric et al., "Optical Signatures of the Aharonov-Bohm Phase in Single-Walled Carbon Nanotubes," Science 304, 1129 (2004). (abstract, full text, news)