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Aharonov-Bohm interference and beating in single-walled carbon-nanotube interferometers
Jien Cao1, Qian Wang, Marco Rolandi
1Department of Chemistry and Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA.
Physical Review Letters
|December 17, 2004
Summary
Low magnetic fields significantly alter conductance in chiral single-walled carbon nanotubes. This modulation, driven by electron interference, reveals unique quantum phenomena in nanoscale structures.
Area of Science:
- Condensed Matter Physics
- Nanotechnology
- Quantum Mechanics
Background:
- Chiral single-walled carbon nanotubes (SWCNTs) exhibit unique electronic properties.
- Understanding quantum interference effects in nanotubes is crucial for electronic applications.
Purpose of the Study:
- To investigate the effect of magnetic fields on the conductance of chiral SWCNTs.
- To explore the underlying quantum interference phenomena responsible for observed modulations.
Main Methods:
- Applying low magnetic fields parallel to the SWCNT axis.
- Analyzing conductance measurements in the Fabry-Perot interference regime.
- Investigating Aharonov-Bohm type interference between subbands.
Main Results:
- Observed large modulations in the p-channel/valence band conductance.
- Identified beating in interference patterns due to two field-induced subbands.
- Determined a pseudoperiod much smaller than the flux quantum (Φ0 = h/e).
Conclusions:
- SWCNTs demonstrate the Aharonov-Bohm effect in the smallest known cylinders.
- Rich interference and beating phenomena arise from well-defined molecular orbitals.
- Chirality plays a key role in the observed quantum effects in SWCNTs.