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Updated: May 31, 2026
08:10
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Published on: February 5, 2017
Quantum effects in a cylindrical carbon-nanotube capacitor
Kazuyuki Uchida1, Susumu Okada, Kenji Shiraishi
1Center for Computational Sciences and Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan. CREST, Japan Science and Technology (JST) Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
Summary
Quantum effects in nano-scale coaxial-cylindrical capacitors made of double-walled carbon nanotubes lead to unique charge distributions and altered capacitance values compared to classical predictions.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Capacitance in nanoscale devices is crucial for electronic applications.
- Carbon nanotubes offer unique electronic properties for novel capacitor designs.
Purpose of the Study:
- To theoretically investigate electric polarization and capacitance in a double-walled carbon nanotube capacitor.
- To understand quantum mechanical effects on charge distribution and capacitance.
Main Methods:
- First-principles density-functional theory (DFT) calculations.
- Enforced Fermi-energy difference scheme applied to a (6,0)@(36,0) double-walled carbon nanotube model.
Main Results:
- Observed quantum mechanical charge spilling: outward from the inner tube and inward to the outer tube.
- Electrostatic capacitance exceeds classical predictions due to charge spill effects.
- Total capacitance is less than electrostatic capacitance, influenced by electrode density of states (DOS).
Conclusions:
- Two key quantum effects significantly impact capacitance in carbon nanotube capacitors.
- These findings are vital for the effective design and optimization of carbon nanotube-based electronic devices.
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