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The Kondo effect is the many-body screening of a local spin by a cloud of electrons at very low temperature. It has been proposed as an explanation of the zero-bias anomaly in quantum point contacts where interactions drive a spontaneous…

Mesoscale and Nanoscale Physics · Physics 2016-03-30 B. Brun , F. Martins , S. Faniel , B. Hackens , A. Cavanna , C. Ulysse , A. Ouerghi , U. Gennser , D. Mailly , P. Simon , S. Huant , V. Bayot , M. Sanquer , H. Sellier

The Kondo effect of a Co atom on Cu(100) was investigated with a low-temperature scanning tunneling microscope using a monoatomically sharp nickel tip. Upon a tip-Co contact, the differential conductance spectra exhibit a spin-split…

Mesoscale and Nanoscale Physics · Physics 2016-10-17 D. -J. Choi , S. Guissart , M. Ormaza , N. Bachellier , O. Bengone , P. Simon , L. Limot

We study an influence of a finite magnetic field on a small spin-degenerate quantum dot with even number of electrons, attached to metallic leads. It is shown that, under certain conditions, the low energy physics of the system can be…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 M. Pustilnik , Y. Avishai , K. Kikoin

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

The zero-bias anomaly at low temperatures, originated by the Kondo effect when an electric current flows through a system formed by a spin-$1/2$ quantum dot and two metallic contacts is theoretically investigated. In particular, we compare…

Strongly Correlated Electrons · Physics 2018-12-07 Diego Pérez Daroca , Pablo Roura-Bas , Armando A. Aligia

We report measurements of the Kondo effect in a double quantum dot (DQD), where the orbital states act as pseudospin states whose degeneracy contributes to Kondo screening. Standard transport spectroscopy as a function of the bias voltage…

Mesoscale and Nanoscale Physics · Physics 2013-05-30 S. Amasha , A. J. Keller , I. G. Rau , A. Carmi , J. A. Katine , H. Shtrikman , Y. Oreg , D. Goldhaber-Gordon

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

Using nonequilibrium perturbation theory, we investigate the nonlinear transport through a quantum dot in the Kondo regime in the presence of a magnetic field. We calculate the leading logarithmic corrections to the local magnetization and…

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

We investigate the Kondo effect in a quadruple quantum dot device of coupled-double quantum dots (DQDs), which simultaneously contains intra-DQDs and inter-DQDs coupling. A variety of novel behaviors are observed. The differential…

Mesoscale and Nanoscale Physics · Physics 2016-07-19 Runan Shang , Hai-Ou Li , Gang Cao , Guodong Yu , Ming Xiao , Tao Tu , Guang-Can Guo , Hongwen Jiang , A. M. Chang , Guo-Ping Guo

We investigate the Kondo effect in two-dimensional disordered electron systems using a finite-temperature quantum Monte Carlo method. Depending on the position of a magnetic impurity, the local moment is screened or unscreened by the spin…

Strongly Correlated Electrons · Physics 2015-06-24 S. Suga , T. Ohashi

We demonstrate delicate control over the Kondo effect and its interplay with quantum interference in an Aharonov-Bohm interferometer containing one Kondo dot and one noninteracting dot. It is shown that the Kondo resonance undergoes a…

Strongly Correlated Electrons · Physics 2013-06-10 Tie-Feng Fang , Hong-Gang Luo

The Kondo problem, for a quantum dot (QD), subjected to an external bias, is analyzed in the limit of infinite Coulomb repulsion by using a consistent equations of motion method based on a slave-boson Hamiltonian. Utilizing a strict…

Strongly Correlated Electrons · Physics 2009-11-11 R. C. Monreal , F. Flores

Correlation effects on electron transport through a system of T-shaped double-dots are investigated, for which only one of the dots is directly connected to the leads. We evaluate the local density of states and the conductance by means of…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Yusuke Takazawa , Yoshiki Imai , Norio Kawakami

Quantum devices such as spin qubits have been extensively investigated in electrostatically confined quantum dots using high-quality semiconductor heterostructures like GaAs and Si. Here, we present the first demonstration of…

Linear conductance across a large quantum dot via a single level e_0 with large hybridization to the contacts is strongly sensitive to quasi-bound states localized in the dot and weakly coupled to e_0. It oscillates with the gate voltage…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Piotr Stefanski , Arturo Tagliacozzo , Bogdan R. Bulka

We report the observation of Kondo physics in a spin- 3/2 hole quantum dot. The dot is formed close to pinch-off in a hole quantum wire defined in an undoped AlGaAs/GaAs heterostructure. We clearly observe two distinctive hallmarks of…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 O. Klochan , A. P. Micolich , A. R. Hamilton , K. Trunov , D. Reuter , A. D. Wieck

We consider a strongly interacting quantum dot connected to two leads held at quite different temperatures. Our aim is to study the behavior of the Kondo effect in the presence of large thermal biases. We use three different approaches,…

Mesoscale and Nanoscale Physics · Physics 2017-09-04 Miguel A. Sierra , David Sanchez , Rosa Lopez

We study theoretically the linear conductance of a quantum dot connected to ferromagnetic leads. The dot level is split due to a non-collinear magnetic field or intrinsic magnetization. The system is studied in the non-interacting…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Jonas N. Pedersen , Jesper Q. Thomassen , Karsten Flensberg

The transport properties of a double quantum-dot device with one of the dots coupled to perfect conductors are analyzed using the numerical renormalization group technique and slave-boson mean-field theory. The coupling between the dots…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 P. S. Cornaglia , D. R. Grempel

We investigate spin-polarized transport phenomena through double quantum dots coupled to ferromagnetic leads in series. By means of the slave-boson mean-field approximation, we calculate the conductance in the Kondo regime for two different…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Yoichi Tanaka , Norio Kawakami