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Excitons in Carbon Nanotubes with Broken Time-Reversal Symmetry

S. Zaric·G. N. Ostojic·J. Shaver·J. Kono·O. Portugall·P. H. Frings·G. L. J. A. Rikken·M. Furis·S. A. Crooker·X. Wei·V. C. Moore·R. H. Hauge·R. E. Smalley
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Abstract

Near-infrared magneto-optical spectroscopy of single-walled carbon nanotubes reveals two absorption peaks with an equal strength at high magnetic fields ($>$ 55 T). We show that the peak separation is determined by the Aharonov-Bohm phase due to the tube-threading magnetic flux, which breaks the time-reversal symmetry and lifts the valley degeneracy. This field-induced symmetry breaking thus overcomes the Coulomb-induced intervalley mixing which is predicted to make the lowest exciton state optically inactive (or ``dark'').

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S. Zaric, G. N. Ostojic, J. Shaver, J. Kono, O. Portugall, P. H. Frings, G. L. J. A. Rikken, M. Furis, S. A. Crooker, X. Wei, V. C. Moore, R. H. Hauge, R. E. Smalley. 2005-09-16. Excitons in Carbon Nanotubes with Broken Time-Reversal Symmetry. https://doi.org/10.1103/physrevlett.96.016406

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