Related papers: Exchange effects in spin polarized transport throu…
We analyzed the effects of a spin voltage as well as a conventionally applied voltage in a QD system with a different number of quantum states in the dot region in presence of Coulombic interaction between the quantum dot and two leads. We…
The out-of-equilibrium electron transport of carbon nanotube semiconducting quantum dot placed in a magnetic field is studied in the Kondo regime by means of the non-equilibrium Green functions. The equation of motion method is used. For…
The transport properties of finite nanotubes placed in a magnetic field parallel to their axes are investigated. Upon including spin-orbit coupling and curvature effects, two main phenomena are analyzed which crucially depend on the tube's…
We investigate the electronic transport through a suspended carbon-nanotube quantum dot. In the presence of a magnetic field perpendicular to the nanotube and a nearby metallic gate, two forces act on the electrons: the Laplace and the…
We report magnetic field spectroscopy measurements in carbon nanotube quantum dots exhibiting four-fold shell structure in the energy level spectrum. The magnetic field induces a large splitting between the two orbital states of each shell,…
We have measured the differential conductance dI/dV of individual multi-wall carbon nanotubes (MWNT) of different lengths. A cross-over from wire-like (long tubes) to dot-like (short tubes) behavior is observed. dI/dV is dominated by random…
Recent conductance measurements on multi-wall carbon nanotubes (CNTs) reveal an effective behavior similar to disordered single-wall CNTs. This is due to the fact that electric current flows essentially through the outermost shell and is…
Spin-charge states of correlated electrons in a one-dimensional quantum dot attached to interacting leads are studied in the non-linear transport regime. With non-symmetric tunnel barriers, regions of negative differential conductance…
Spin-coherent quantum transport in carbon nanotube magnetic tunnel junctions was investigated theoretically. A spin-valve effect is found for metallic, armchair tubes, with a magneto-conductance ratio ranging up to 20%. Because of the…
The Kondo-effect is a many-body phenomenon arising due to conduction electrons scattering off a localized spin. Coherent spin-flip scattering off such a quantum impurity correlates the conduction electrons and at low temperature this leads…
We demonstrate spin injection and detection in single wall carbon nanotubes using a 4-terminal, non-local geometry. This measurement geometry completely separates the charge and spin circuits. Hence all spurious magnetoresistance effects…
We present studies of the Coulomb blockade and Kondo regimes of transport through a quantum dot connected to current leads through spin-polarizing quantum point contacts (QPCs). This structure, arising from the effect of lateral spin-orbit…
We present quantum transport measurements of interacting parallel quantum dots formed in the strands of a carbon nanotube rope. In this molecular quantum dot system, transport is dominated by one quantum dot, while additional resonances…
The low energy spectrum of finite size metallic single-walled carbon nanotubes SWNTs) is determined. Starting from a tight binding model for the $p_{z}$ electrons, we derive the low energy Hamiltonian containing all relevant scattering…
Kondo correlations are responsible for the emergence of a zero-bias peak in the low temperature differential conductance of Coulomb blockaded quantum dots. In the presence of a global SU(2)$\otimes$SU(2) symmetry, which can be realized in…
We study the electronic transport through a noncollinear single-electron spin-valve transistor. It consists of a small metallic island weakly coupled to two ferromagnetic leads with noncollinear magnetization directions. The electric…
We review the peculiarities of transport through a quantum dot caused by the spin transition in its ground state. Such transitions can be induced by a magnetic field. Tunneling of electrons between the dot and leads mixes the states…
We study theoretically the Kondo effect in carbon nanotube quantum dot attached to polarized electrodes. Since both spin and orbit degrees of freedom are involved in such a system, the electrode polarization contains the spin- and…
We develop a theory of electron transport through quantum dots that are weakly coupled to ferromagnetic leads. The theory covers both the linear and nonlinear transport regime, takes non-collinear magnetization of the leads into account,…
We investigate the effects of spin-orbit interaction (SOI) on the exchange cotunneling through a spinful Coulomb blockaded quantum dot. In the case of zero magnetic field, Kondo effect is shown to take place via a Kramers doublet and the…