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The Andreev transport properties of double quantum dot based Cooper pair splitters with one superconducting and two normal leads are studied theoretically in the Kondo regime. The influence of the superconducting pairing correlations on the…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 K. Wrzesniewski , I. Weymann

We report on a comprehensive study of spin-1/2 Kondo effect in a strongly-coupled quantum dot realized in a high-quality InAs nanowire. The nanowire quantum dot is relatively symmetrically coupled to its two leads, so the Kondo effect…

We investigate the influence of spin-orbit coupling on the Kondo effects in carbon nanotube quantum dots, using the numerical renormalization group technique. A sufficiently large spin-orbit coupling is shown to destroy the SU(4) Kondo…

Strongly Correlated Electrons · Physics 2010-03-11 Martin R. Galpin , Frederic W. Jayatilaka , David E. Logan , Frithjof B. Anders

We investigate a lateral semiconductor quantum dot with a large number of electrons in the limit of strong coupling to the leads. A Kondo effect is observed and can be tuned in a perpendicular magnetic field. This Kondo effect does not…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 C. Fuhner , U. F. Keyser , R. J. Haug , D. Reuter , A. D. Wieck

In this paper we study the thermopower of a quantum dot connected to two leads in the presence of Kondo correlation by employing a modified second-order perturbation scheme at nonequilibrium. A simple scheme, Ng's ansatz [Phys. Rev. Lett.…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Bing Dong , X. L. Lei

We discuss a device --- a purely capacitively coupled interacting spinless triple quantum dot system --- for the observation of the SU(3) Kondo effect. Unlike more familiar SU(2) and SU(4) Kondo effects in quantum dot devices which lead to…

Strongly Correlated Electrons · Physics 2015-06-11 Rosa Lopez , Tomaz Rejec , Jan Martinek , Rok Zitko

This paper is devoted to a systematic exposure of the Kondo physics in quantum dots for which the low energy spin excitations consist of a few different spin multiplets $|S_{i}M_{i}>$. Under certain conditions (to be explained below) some…

Strongly Correlated Electrons · Physics 2007-05-23 Tetyana Kuzmenko , Konstantin Kikoin , Yshai Avishai

We study the Kondo effect in a quantum dot which is coupled to ferromagnetic leads and analyse its properties as a function of the spin polarization of the leads. Based on a scaling approach we predict that for parallel alignment of the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. Martinek , Y. Utsumi , H. Imamura , J. Barnas , S. Maekawa , J. König , G. Schön

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

Electron tunneling through quantum-dots side coupled to a quantum wire, in equilibrium and nonequilibrium Kondo regime, is studied. The mean-field finite-$U$ slave-boson formalism is used to obtain the solution of the problem. We have found…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Pedro A. Orellana , Gustavo A. Lara , Enrique V. Anda

We present a theoretical analysis of the effects of uniaxial magnetic anisotropy and contact-induced exchange field on the underscreened Kondo effect in S=1 magnetic quantum dots coupled to ferromagnetic leads. First, by using the…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Maciej Misiorny , Ireneusz Weymann , Józef Barnaś

A new theoretical method is introduced to study coherent electron transport in an interacting multilevel quantum dot. The method yields the correct behavior both in the limit of weak and strong coupling to the leads, giving a unified…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. Levy Yeyati , F. Flores , A. Martin-Rodero

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…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 J. Paaske , A. Andersen , K. Flensberg

We calculate the thermopower of a quantum dot described by two doublets hybridized with two degenerate bands of two conducting leads, conserving orbital (band) and spin quantum numbers, as a function of the temperature $T$ and a splitting…

Strongly Correlated Electrons · Physics 2012-10-23 P. Roura-Bas , L. Tosi , A. A. Aligia , P. S. Cornaglia

We observe a strong Kondo effect in a semiconductor quantum dot when a small magnetic field is applied. The Coulomb blockade for electron tunneling is overcome completely by the Kondo effect and the conductance reaches the unitary-limit…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 W. G. van der Wiel , S. De Franceschi , T. Fujisawa , J. M. Elzerman , S. Tarucha , L. P. Kouwenhoven

We investigate the charge fluctuations of a single-electron box (metallic grain) coupled to a lead via a smaller quantum dot in the Kondo regime. The most interesting aspect of this problem resides in the interplay between spin Kondo…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Karyn Le Hur , Pascal Simon , Laszlo Borda

The Kondo effect in coupled quantum dots is investigated theoretically under magnetic fields. We show that the magnetoconductance (MC) illustrates peak structures of the Kondo resonant spectra. When the dot-dot tunneling coupling $V_C$ is…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Tomosuke Aono , Mikio Eto

We study the Kondo effect in a model system of a quantum dot embedded in an Aharanov-Bohm ring connected to two leads. By transforming to the scattering basis of the direct inter-lead tunneling, we are able to describe precisely how the…

Mesoscale and Nanoscale Physics · Physics 2010-10-15 Justin Malecki , Ian Affleck

We calculate the finite temperature and non-equilibrium electric current through systems described generically at low energy by a singlet and \emph{two} spin doublets for $N$ and $N \pm 1$ electrons respectively, coupled asymmetrically to…

Strongly Correlated Electrons · Physics 2011-08-24 P. Roura-Bas , L. Tosi , A. A. Aligia , K. Hallberg

We investigate the effects induced by spin polarization in the contacts attached to a serial double quantum dot. The polarization generates effective magnetic fields and suppresses the Kondo effect in each dot. The super-exchange…

Mesoscale and Nanoscale Physics · Physics 2012-06-14 Rok Žitko , Jong Soo Lim , Rosa Lopez , Jan Martinek , Pascal Simon