Excitons in carbon nanotubes with broken time-reversal symmetry.
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).
Zaric
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Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA.
Ostojic
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Shaver
J
J
Kono
J
J
Portugall
O
O
Frings
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Rikken
G L J A
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Furis
M
M
Crooker
S A
SA
Wei
X
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Moore
V C
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Hauge
R H
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Smalley
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