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We study transport through a double quantum dot system in which each quantum dot is coupled to a phonon mode. Such a system can be realized, e.g., using a suspended carbon nanotube. We find that the interplay between strong electron-phonon…

Mesoscale and Nanoscale Physics · Physics 2013-11-26 Stefan Walter , Björn Trauzettel , Thomas L. Schmidt

Spin-polarized transport through a quantum dot strongly coupled to ferromagnetic electrodes with non-collinear magnetic moments is analyzed theoretically in terms of the non-equilibrium Green function formalism. Electrons in the dot are…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 R. Swirkowicz , M. Wilczynski , J. Barnas

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…

Strongly Correlated Electrons · Physics 2007-05-23 J. Paaske , A. Rosch , P. Woelfle , N. Mason , C. M. Marcus , J. Nygard

Non-equilibrium Green's function technique has been used to calculate spin-dependent electronic transport through a quantum dot in the Kondo regime. The dot is described by the Anderson Hamiltonian and is coupled either symmetrically or…

Other Condensed Matter · Physics 2009-11-11 R. Swirkowicz , M. Wilczynski , J. Barnas

The transport properties of nanostructured systems are deeply affected by the geometry of the effective connections to metallic leads. In this work we derive a conductance expression for interacting systems whose connectivity geometries do…

Mesoscale and Nanoscale Physics · Physics 2017-09-15 Luis G. G. V. Dias da Silva , Caio H. Lewenkopf , Edson Vernek , Gerson J. Ferreira , Sergio E. Ulloa

We discuss the physics of a of a spin-1 quantum dot, coupled to two metallic leads and develop a simple model for the temperature dependence of its conductance. Such quantum dots are described by a two-channel Kondo model with asymmetric…

Strongly Correlated Electrons · Physics 2007-08-15 Anna Posazhennikova , Babak Bayani , P. Coleman

We present the transport properties of a strongly correlated quantum dot attached to two leads with a side coupled non-interacting quantum dot. Transport properties are analyzed using the slave boson mean field theory which is reliable in…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 B. H. Wu , J. C. Cao , Kang-Hun Ahn

We report on electrical transport measurements in a carbon nanotube quantum dot coupled to a normal and a superconducting lead. Depending on the ratio of Kondo temperature $T_{K}$ and superconducting gap $\Delta$ the zero bias conductance…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. R. Graeber , T. Nussbaumer , W. Belzig , C. Schoenenberger

We investigate the effects of voltage induced spin-relaxation in a quantum dot in the Kondo regime. Using nonequilibrium perturbation theory, we determine the joint effect of self-energy and vertex corrections to the conduction electron…

Strongly Correlated Electrons · Physics 2007-05-23 J. Paaske , A. Rosch , J. Kroha , P. Wölfle

The nonlinear conductance observed in a quantum point contact is theoretically reproduced for the entire range of applied bias. The single-impurity Anderson model with two reservoirs at different chemical potentials is studied for a…

Mesoscale and Nanoscale Physics · Physics 2013-01-25 Jongbae Hong

We study the transport behavior induced by a small bias voltage through a quantum dot connected to one-channel disordered wires by means of a quantum Monte Carlo method. We model the quantum dot by the Hubbard-Anderson impurity and the…

Strongly Correlated Electrons · Physics 2013-01-01 Alberto Camjayi , Liliana Arrachea

We investigate linear and non-linear transport in a double quantum dot system weakly coupled to spin-polarized leads. In the linear regime, the conductance as well as the non-equilibrium spin accumulation are evaluated in analytic form. The…

Mesoscale and Nanoscale Physics · Physics 2008-07-01 Ralph Peter Hornberger , Sonja Koller , Georg Begemann , Andrea Donarini , Milena Grifoni

Strong correlation effects on electron transport through a spinless quantum dot are considered. When two single-particle levels in the quantum dot are degenerate, a conserved pseudospin degree of freedom appears for general tunneling matrix…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hyun-Woo Lee , Sejoong Kim

We study the full counting statistics of electronic transport through a single-level quantum dot weakly coupled to two leads, with either one or both of them being ferromagnetic. The interplay of Coulomb interaction and finite spin…

Mesoscale and Nanoscale Physics · Physics 2009-06-05 Stephan Lindebaum , Daniel Urban , Jürgen König

We study the transport properties of a quantum dot coupled to a normal and a superconducting lead. The dot is represented by a generalized Anderson model. Correlation effects are taken into account by an appropriate self-energy which…

Strongly Correlated Electrons · Physics 2009-10-31 J. C. Cuevas , A. Levy Yeyati , A. Martin-Rodero

We investigate the nonequilibrium phenomena through the quantum dot coupled to the normal and superconducting leads using a weak-coupling continuous-time Monte Carlo method. Calculating the time evolution of particle number, double…

Strongly Correlated Electrons · Physics 2013-03-21 Akihisa Koga

Molecular electronics offers unique scientific and technological possibilities, resulting from both the nanometre scale of the devices and their reproducible chemical complexity. Two fundamental yet different effects, with no classical…

Mesoscale and Nanoscale Physics · Physics 2017-05-12 Andrew K. Mitchell , Kim G. L. Pedersen , Per Hedegaard , Jens Paaske

We study the electric and thermoelectric transport properties of correlated quantum dots coupled to two ferromagnetic leads and one superconducting electrode. Transport through such hybrid devices depends on the interplay of…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 Krzysztof P. Wojcik , Ireneusz Weymann

In this lecture note we focus our attention to quantum dot systems where exotic strongly correlated behavior develops due to the presence of orbital or charge degrees of freedom. After giving a concise overview of the theory of transport…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 G. Zarand

A small quantum ring with less than 10 electrons was studied by transport spectroscopy. For strong coupling to the leads a Kondo effect is observed and used to characterize the spin structure of the system in a wide range of magnetic…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 U. F. Keyser , C. Fuhner , S. Borck , R. J. Haug , M. Bichler , G. Abstreiter , W. Wegscheider