Persistent Orbital Degeneracy in Carbon Nanotubes

Abstract

The quantum-mechanical orbitals in carbon nanotubes are doubly degenerate over a large number of states in the Coulomb blockade regime. We argue that this experimental observation indicates that electrons are reflected without mode mixing at the nanotube-metal contacts. Two electrons occupying a pair of degenerate orbitals (a ``shell'') are found to form a triplet state starting from zero magnetic field. Finally, we observe unexpected low-energy excitations at complete filling of a four-electron shell.

6 pages, 4 figures

References in corpus (13)

• The Statistical Theory of Quantum Dots
• Quantum Effects in Coulomb Blockade
• Disorder, pseudospins, and backscattering in carbon nanotubes
• Conductance of a quantum wire in the Wigner crystal regime
• Multi-wall carbon nanotubes as quantum dots
• Shell filling in closed single-wall carbon nanotube quantum dots
• Conductance of a quantum wire at low electron density
• Four-electron shell structures and an interacting two-electron system in carbon nanotube quantum dots
• Spin configurations of carbon nanotube in a nonuniform external potential
• Electronic Transport Spectroscopy of Carbon Nanotubes in a Magnetic Field
• Electronic excitation spectrum of metallic carbon nanotubes
• On the Kondo effect in carbon nanotubes at half halfing
• Addition Energies of Fullerenes and Nanotubes as Quantum Dots: The Role of Symmetry

Cited by in corpus (16)

• Coupling of Spin and Orbital Motion of Electrons in Carbon Nanotubes
• SU(4) and SU(2) Kondo Effects in Carbon Nanotube Quantum Dots
• Evolution of SU(4) Transport Regimes in Carbon Nanotube Quantum Dots
• Zero-bias conductance in carbon nanotube quantum dots
• Angular momentum and topology in semiconducting single-wall carbon nanotubes
• Valley coupling in finite-length metallic single-wall carbon nanotubes
• The two classes of low energy spectra in finite carbon nanotubes
• Kondo effect of cobalt adatom on zigzag graphene nanoribbon
• Transverse field-induced effects in carbon nanotubes
• Ground State and Excitations of Quantum Dots with "Magnetic Impurities"
• Band-Gap-Dependent Electronic Compressibility of Carbon Nanotubes in the Wigner Crystal Regime
• Cotunneling renormalization in carbon nanotube quantum dots
• Spin effects in single-electron transport through carbon nanotube quantum dots
• Coupling of shells in a carbon nanotube quantum dot
• Accessing nanotube bands via crossed electric and magnetic fields
• Gate-dependent spin-orbit coupling in multi-electron carbon nanotubes