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We theoretically investigate the Kondo effect of a T-shaped triple-quantum-dot structure, by means of the numerical renormalization group method. It is found that at the point of electron-hole symmetry, the system's entropy has…

Mesoscale and Nanoscale Physics · Physics 2020-08-26 Guang-Yu Yi , Cui Jiang , Lian-Lian Zhang , Su-Rui Zhong , Hao Chu , Wei-Jiang Gong

We generalize the iterative diagonalization procedure adopted in method of numerical renormalization group to analyze the Kondo effect in strong magnetic fields, where the density of states for itinerary electrons at the chemical potential…

Strongly Correlated Electrons · Physics 2022-11-23 Po-Hao Chou , Chung-Hou Chung , Chung-Yu Mou

We systematically study the influence of ferromagnetic leads on the Kondo resonance in a quantum dot tuned to the local moment regime. We employ Wilson's numerical renormalization group method, extended to handle leads with a spin…

Mesoscale and Nanoscale Physics · Physics 2011-11-10 M. Sindel , L. Borda , J. Martinek , R. Bulla , J. Koenig , G. Schoen , S. Maekawa , J. von Delft

The interplay between the coupling of an interacting quantum dot to a conduction band and its connection to localized levels has been studied in a triple quantum dot arrangement. The electronic Dicke effect, resulting from quasi-resonant…

Mesoscale and Nanoscale Physics · Physics 2010-10-18 E. Vernek , P. A. Orellana , S. E. Ulloa

We consider the spin and orbital Kondo effect in a parallel arrangement of two strongly electrostatically coupled quantum dots. Increasing the exchange of electrons between the dots through the attached leads induces the transition between…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 A. L. Chudnovskiy

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

A double quantum dot device, connected to two channels that only see each other through interdot Coulomb repulsion, is analyzed using the numerical renormalization group technique. By using a two-impurity Anderson model, and parameter…

Strongly Correlated Electrons · Physics 2022-05-13 E. Vernek , C. A. Busser , E. V. Anda , A. E. Feiguin , G. B. Martins

We consider a two-orbital impurity system with intra and inter-level Coulomb repulsion that is coupled to a single conduction channel. This situation can generically occur in multilevel quantum dots or in systems of coupled quantum dots.…

Strongly Correlated Electrons · Physics 2017-07-05 Arturo Wong , Anh T. Ngo , Sergio E. Ulloa

Kondo conduction has been observed in a quantum dot with an even number of electrons at the Triplet-Singlet degeneracy point produced by applying a small magnetic field $B$ orthogonal to the dot plane. At a much larger field $ B \sim B_*$,…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 D. Giuliano , B. Jouault , A. Tagliacozzo

We study the finite size effect of the Kondo screening cloud in a double-quantum-dot setup via a large-N slave-boson mean-field theory. In this setup, one of the dots is embedded in a close metallic ring with a finite size $L$ and the other…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 I-Ling Tsai , Chung-Hou Chung

The effect of a magnetic field on the spectral density of a $\rm{S=1/2}$ Kondo impurity is investigated at zero and finite temperatures by using Wilson's numerical renormalization group method. A splitting of the total spectral density is…

Strongly Correlated Electrons · Physics 2009-10-31 T. A. Costi

We investigate quantum dots in clean single-wall carbon nanotubes with ferromagnetic PdNi-leads in the Kondo regime. In most odd Coulomb valleys the Kondo resonance exhibits a pronounced splitting, which depends on the tunnel coupling to…

Mesoscale and Nanoscale Physics · Physics 2011-10-26 M. Gaass , A. K. Huettel , K. Kang , I. Weymann , J. von Delft , Ch. Strunk

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

The Kondo effect in quantum dots (QDs) - artificial magnetic impurities - attached to ferromagnetic leads is studied with the numerical renormalization group (NRG) method. It is shown that the QD level is spin-split due to presence of…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. Martinek , M. Sindel , L. Borda , J. Barnaś , J. König , G. Schön , J. von Delft

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 consider spin and orbital Kondo effect in a parallel arrangement of two strongly electrostatically coupled quantum dots. Increasing the exchange of electrons between the dots through the attached leads induces a smooth crossover between…

Mesoscale and Nanoscale Physics · Physics 2007-10-24 A. L. Chudnovskiy , Frank Hellmuth , V. Kagalovsky

Quantum dots in the quantum Hall regime can have pairs of single Slater determinant states that are degenerate in energy. We argue that these pairs of many body states may give rise to a Kondo effect which can be mapped into an ordinary…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Mahn-Soo Choi , Nak Yeon Hwang , S. -R. Eric Yang

We study the Kondo and transport properties of a quantum dot with a single magnetic Mn ion connected to metallic leads. By employing a numerical renormalization group technique we show that depending on the value of ferromagnetic coupling…

Mesoscale and Nanoscale Physics · Physics 2011-10-04 E. vernek , Fanyao Qu , F. M. Souza , J. C. Egues , E. V. Anda

We show a detailed investigation of the split Kondo effect in a carbon nanotube quantum dot with multiple gate electrodes. It is found that the splitting decreases for increasing magnetic field, to result in a recovered zero-bias Kondo…

Mesoscale and Nanoscale Physics · Physics 2011-06-01 A. Eichler , M. Weiss , C. Schönenberger

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