Spin transport across carbon nanotube quantum dots

Abstract

We investigate linear and nonlinear transport in interacting single wall carbon nanotubes (SWCNTs) that are weakly attached to ferromagnetic leads. For the reduced density matrix of a SWCNT quantum dot, equations of motion which account for an arbitrarily vectored polarisation of the contacts are derived. We focus on the case of large diameter nanotubes where exchange effects emerging from short-ranged processes can be excluded and the four-electron periodicity at low bias can be observed. This yields in principle four distinct resonant tunnelling regimes, but due to symmetries in the involved groundstates, each two possess a mirror-symmetry. With a non-collinear configuration, we recover at the 4N <-> 4N+1 / 4N+3 <-> 4N resonances the analytical results known for the angular dependence of the conductance of a single level quantum dot or a metallic island. The two other cases are treated numerically and show on the first glance similar, yet not analytically describable dependences. In the nonlinear regime, negative differential conductance features occur for non-collinear lead magnetisations.

39 pages, 19 figures; revised final published version

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• Magnetoresistance of a quantum dot with spin-active interfaces
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• Linear and nonlinear transport across carbon nanotube quantum dots
• Controlling spin in an electronic interferometer with spin-active interfaces
• Non-Fermi liquid behavior in transport across carbon nanotube quantum dots
• Exchange effects on electron transport through single-electron spin-valve transistors
• Correlated sequential tunneling through a double barrier for interacting one-dimensional electrons
• Ballistic magnetoresistance in small-size carbon nanotubes devices

Cited by in corpus (19)

• Density-operator approaches to transport through interacting quantum dots: Simplifications in fourth-order perturbation theory
• Spin effects in single electron tunneling
• Universality of the Kondo effect in quantum dots with ferromagnetic leads
• A benzene interference single-electron transistor
• Transport through a double quantum dot system with non-collinearly polarized leads
• Spectroscopy and critical temperature of diffusive superconducting/ferromagnetic hybrid structures with spin-active interfaces
• Signatures of spin-orbit interaction in transport properties of finite carbon nanotubes in a parallel magnetic field
• Interference effects in the Coulomb blockade regime: current blocking and spin preparation in symmetric nanojunctions
• Probing the exchange field of a quantum-dot spin valve by a superconducting lead
• Transport through single-wall metallic carbon nanotubes in the cotunneling regime
• Transport across a carbon nanotube quantum dot contacted with ferromagnetic leads: experiment and non-perturbative modeling
• Conductance and current noise of a superconductor/ferromagnet quantum point contact
• Influence of spin waves on transport through a quantum-dot spin valve
• Sources of negative tunneling magneto-resistance in multilevel quantum dots with ferromagnetic contacts
• Dynamical symmetry breaking in vibration-assisted transport through nanostructures
• Exchange effects in spin polarized transport through carbon nanotube quantum dots
• Spectrum and Franck-Condon factors of interacting suspended single-wall carbon nanotubes
• Vibration induced memory effects and switching in ac-driven molecular nanojunctions
• Spin-dependent transport through interacting graphene armchair nanoribbons