Aharonov-Bohm effect in circular carbon nanotubes

We study the interference of interacting electrons in toroidal single-wall carbon nanotubes coupled to metallic electrodes by tunnel junctions. The dc conductance shows resonant features as a function of the gate voltage and the magnetic field. The conductance pattern is determined by the interaction parameter, which in turn can be cross-checked against the exponents governing the transport at high temperatures. The coordinate dependence of the conductance reflects electron correlations in one-dimensional space.Comment: 2 pages, contributed paper to LT-22, style file phbauth.cls is include

Towards single-electron metrology

We review the status of the understanding of single-electron transport (SET) devices with respect to their applicability in metrology. Their envisioned role as the basis of a high-precision electrical standard is outlined and is discussed in the context of other standards. The operation principles of single electron transistors, turnstiles and pumps are explained and the fundamental limits of these devices are discussed in detail. We describe the various physical mechanisms that influence the device uncertainty and review the analytical and numerical methods needed to calculate the intrinsic uncertainty and to optimise the fabrication and operation parameters. Recent experimental results are evaluated and compared with theoretical predictions. Although there are discrepancies between theory and experiments, the intrinsic uncertainty is already small enough to start preparing for the first SET-based metrological applications.Comment: 39 pages, 14 figures. Review paper to be published in International Journal of Modern Physics

Electronic Properties of Armchair Carbon Nanotubes : Bosonization Approach

The phase Hamiltonian of armchair carbon nanotubes at half-filling and away from it is derived from the microscopic lattice model by taking the long range Coulomb interaction into account. We investigate the low energy properties of the system using the renormalization group method. At half-filling, the ground state is a Mott insulator with spin gap, in which the bound states of electrons at different atomic sublattices are formed. The difference from the recent results [Phys. Rev. Lett. 79, 5082 (1997)] away half-filling is clarified.Comment: 4 pages, 1 figure, Revte

Universality of electron correlations in conducting carbon nanotubes

Effective low-energy Hamiltonian of interacting electrons in conducting single-wall carbon nanotubes with arbitrary chirality is derived from the microscopic lattice model. The parameters of the Hamiltonian show very weak dependence on the chiral angle, which makes the low energy properties of conducting chiral nanotubes universal. The strongest Mott-like electron instability at half filling is investigated within the self-consistent harmonic approximation. The energy gaps occur in all modes of elementary excitations and estimate at $0.01-0.1$ eV.Comment: 4 pages, 2 figure