• Corpus ID: 117910747

Direct Observation of Dark Excitons in Individual Carbon Nanotubes: Role of Local Environments

@article{Srivastava2008DirectOO,
  title={Direct Observation of Dark Excitons in Individual Carbon Nanotubes: Role of Local Environments},
  author={A. Srivastava and Han Htoon and Victor I. Klimov and Junichiro Kono},
  journal={arXiv: Mesoscale and Nanoscale Physics},
  year={2008}
}

• A. Srivastava, H. Htoon, +1 author J. Kono
• Published 5 April 2008
• Physics
• arXiv: Mesoscale and Nanoscale Physics

We report the direct observation of the spin-singlet dark excitonic state in individual single-walled carbon nanotubes through low-temperature micro-photoluminescence spectroscopy in magnetic fields. A magnetic field up to 5 T, applied along the nanotube axis, brightened the dark state, leading to the emergence of a new emission peak. The peak rapidly grew in intensity with increasing field at the expense of the originally-dominant bright exciton peak and finally became dominant at fields $>$3 T. This behavior, universally observed for more than 50 nanotubes of different chiralities, can be quantitatively explained through a model incorporating the Aharonov-Bohm effect and intervalley Coulomb mixing, unambiguously proving the existence of dark excitons. The directly measured dark-bright splitting values were 1-4 meV for tube diameters 1.0-1.3 nm. Scatter in the splitting value emphasizes the role of the local environment surrounding a nanotube in determining the excitonic fine structure of single-walled carbon nanotubes.