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The effective spin Hamiltonian of a triple quantum dot with odd electron occupation weakly connected in series with left ($l$) and right ($r$) metal leads is composed of two-channel exchange and co-tunneling terms. Renormalization group…

Strongly Correlated Electrons · Physics 2007-05-23 T. Kuzmenko , K. Kikoin , Y. Avishai

We investigate the influence of an electromagnetic environment, characterized by a finite impedance $Z(\omega)$, on the Kondo effect in quantum dots. The circuit voltage fluctuations couple to charge fluctuations in the dot and influence…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Serge Florens , Pascal Simon , Sabine Andergassen , Denis Feinberg

We study the spin-valley Kondo effect of a silicon quantum dot occupied by $% \mathcal{N}$ electrons, with $\mathcal{N}$ up to four. We show that the Kondo resonance appears in the $\mathcal{N}=1,2,3$ Coulomb blockade regimes, but not in…

Materials Science · Physics 2019-09-04 Shiueyuan Shiau , Robert Joynt

The Kondo effect is a cornerstone in the study of strongly correlated fermions. The coherent exchange coupling of conduction electrons to local magnetic moments gives rise to a Kondo cloud that screens the impurity spin. Whereas complete…

We consider the transport properties in an applied magnetic field of the spin S=1/2 Kondo model with ferromagnetic exchange coupling to electronic reservoirs, a description relevant for the strong coupling limit of underscreened spin S=1…

Mesoscale and Nanoscale Physics · Physics 2013-07-15 Mathias Cabrera Cano , Serge Florens

We elaborate on the recently introduced concept of reentrant Kondo effect in quantum impurities/dots coupled to hybrid metal-semiconductor contacts [G.~Diniz {\em et al.}, Phys. Rev. B {\bf 101}, 125115 (2020)]. By noticing the equivalence…

Mesoscale and Nanoscale Physics · Physics 2021-08-04 Peter Zalom , Tomáš Novotný

We study electron transport through a serial double quantum dot with Rashba spin-orbit interaction (SOI) and Zeeman field of amplitude B in presence of local Coulomb repulsion. The linear conductance as a function of a gate voltage Vg…

Strongly Correlated Electrons · Physics 2011-03-15 S. Grap , S. Andergassen , J. Paaske , V. Meden

We study the Kondo effect in multiple-dot systems for which the inter- as well as intra-dot Coulomb repulsions are strong, and the inter-dot tunneling is small. The application of the Ward-Takahashi identity to the inter-dot dynamical…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Rui Sakano , Norio Kawakami

Spin-dependent electronic transport through a quantum dot has been analyzed theoretically in the cotunneling regime by means of the second-order perturbation theory. The system is described by the impurity Anderson Hamiltonian with…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 I. Weymann , J. Barnas

In this work,we study the Kondo effect of a quantum dot (QD) connected to leads and to a discrete set of one particle states provided by a quantum box represented by a quantum ring (QR) pierced by a magnetic flux side attached to the QD.…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 V. M. Apel , Pedro A. Orellana , Monica Pacheco , E. V. Anda

The large, level-dependent g-factors in an InSb nanowire quantum dot allow for the occurrence of a variety of level crossings in the dot. While we observe the standard conductance enhancement in the Coulomb blockade region for aligned…

Mesoscale and Nanoscale Physics · Physics 2010-05-07 H. A. Nilsson , O. Karlström , M. Larsson , P. Caroff , J. N. Pedersen , L. Samuelson , A. Wacker , L. E. Wernersson , H. Q. Xu

By means of a diagram technique for Hubbard operators we show the existence of a spin-dependent renormalization of the localized levels in an interacting region, e.g. quantum dot, modeled by the Anderson Hamiltonian with two conduction…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 J. Fransson , O. Eriksson , I. Sandalov

Electron transport through parallel double quantum dot system with interdot tunneling and strong on-site Coulomb interaction is studied in the Kondo regime by using the finite-$U$ slave boson technique. For a system of quantum dots with…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Guo-Hui Ding , C. K. Kim , K. Nahm

We study the differential conductance in the Kondo regime of a quantum dot coupled to multiple leads. When the bias is applied symmetrically on two of the leads ($V$ and $-V$, as usual in experiments), while the others are grounded, the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 M. Tolea , I. V. Dinu , A. Aldea

Recently, the issue of whether the Kondo problem in quantum dots at large bias is a weak-coupling problem or not has been raised. In this paper, we revisit this problem by carefully analyzing a corresponding model in the solvable limit --…

Strongly Correlated Electrons · Physics 2009-11-07 Yu-Wen Lee , Yu-Li Lee

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…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. Pustilnik , L. I. Glazman , D. H. Cobden , L. P. Kouwenhoven

Using the modified perturbation theory, we theoretically study the nonequilibrium Andreev transport through a quantum dot coupled to normal and superconducting leads (N-QD-S), which is strongly influenced by the Kondo and superconducting…

Mesoscale and Nanoscale Physics · Physics 2015-03-18 Yasuhiro Yamada , Yoichi Tanaka , Norio Kawakami

The ground-state properties of quartet quantum-dot arrays are studied using the numerical renormalization group (NRG) method with a four-site Hubbard model connected to two non-interacting leads. Specifically, we calculate the conductance…

Strongly Correlated Electrons · Physics 2007-05-23 Yunori Nisikawa , Akira Oguri

We study the transport through a quantum dot, in the Kondo Coulomb blockade valley, embedded in a mesoscopic device with finite wires. The quantization of states in the circuit that hosts the quantum dot gives rise to finite size effects.…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 P. S. Cornaglia , C. A. Balseiro

Numerical analysis of the simplest odd-numbered system of coupled quantum dots reveals an interplay between magnetic ordering, charge fluctuations and the tendency of itinerant electrons in the leads to screen magnetic moments. The…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 R. Zitko , J. Bonca , A. Ramsak , T. Rejec