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We study two quantum dots embedded in the arms of an Aharonov-Bohm ring threaded by a magnetic flux. The system can be described by an effective one-impurity Anderson model with an energy- and flux-dependent density of states. For specific…

Mesoscale and Nanoscale Physics · Physics 2009-04-27 Luis G. G. V. Dias da Silva , Nancy Sandler , Pascal Simon , Kevin Ingersent , Sergio E. Ulloa

We investigate the effects of spin-polarized leads on the Kondo physics of a quantum dot using the numerical renormalization group method. Our study demonstrates in an unambiguous way that the Kondo effect is not necessarily suppressed by…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Mahn-Soo Choi , David Sanchez , Rosa Lopez

The interplay between unconventional Cooper pairing and quantum states associated with atomic scale defects is a frontier of research with many open questions. So far, only a few of the high-temperature superconductors allow this intricate…

We investigate serial double quantum dot systems with on-site and inter-site interaction by means of Sch\"onhammer-Gunnarsson projection-operator method. The ground state is established by the competition between extended Kondo phases and…

Mesoscale and Nanoscale Physics · Physics 2007-12-20 Jernej Mravlje , Anton Ramsak , Tomaz Rejec

The magnetization of semiconductor quantum dots in the presence of spin-orbit coupling and interactions is investigated numerically. When the dot is occupied by two electrons we find that a level crossing between the two lowest many-body…

Strongly Correlated Electrons · Physics 2011-01-20 Yuval Weiss , Moshe Goldstein , Richard Berkovits

A detailed analysis of the Kondo effect of a magnetic impurity in a zigzag graphene nanoribbon is addressed. An adatom is coupled to the graphene nanoribbon via a hybridization amplitude $\Gamma_{imp}$ in a hollow or top site configuration.…

Strongly Correlated Electrons · Physics 2018-04-04 G. S. Diniz , G. I. Luiz , A. Latgé , E. Vernek

The interplay between superconductivity and the Kondo effect has stimulated significant interest in condensed matter physics. They compete when their critical temperatures are close and can give rise to a quantum phase transition that can…

Mesoscale and Nanoscale Physics · Physics 2024-07-25 M. -T. Deng , C. -L. Yu , G. -Y. Huang , R. Lopez , P. Caroff , S. G. Ghalamestani , G. Platero , H. Q. Xu

The anomalous ground state phase shift in S/AF/S Josephson junctions in the presence of the Rashba SO-coupling is predicted and numerically investigated. It is found to be a consequence of the uncompensated magnetic moment at the S/AF…

Superconductivity · Physics 2019-11-19 D. S. Rabinovich , I. V. Bobkova , A. M. Bobkov

Supercurrent transport is experimentally studied in a Josephson junction hosting a double quantum dot (DQD) with tunable symmetries. The QDs are parallel-coupled to two superconducting contacts and can be tuned between strong inter-dot…

Mesoscale and Nanoscale Physics · Physics 2022-12-14 Rousan Debbarma , Markus Aspegren , Florinda Viñas Boström , Sebastian Lehmann , Kimberly Dick , Claes Thelander

We analyze the optically induced Kondo effect in the absorption spectrum for a quantum dot with an even number of electrons, for which the Kondo effect does not occur in the ground state. The Kondo exchange couplings generated for…

Condensed Matter · Physics 2007-05-23 T. Fujii , A. Furusaki , N. Kawakami , M. Sigrist

We investigate the influence of an additional bosonic bath onto the real-time dynamics of a localized orbital coupled to conduction band with an energy-dependent coupling function $\Gamma(\varepsilon) \propto |\varepsilon|^r$. Recently, a…

Strongly Correlated Electrons · Physics 2015-12-22 Christian Kleine , Frithjof B. Anders

The Josephson effect describes supercurrent flowing through a junction connecting two superconducting leads by a thin barrier [1]. This current is driven by a superconducting phase difference $\phi$ between the leads. In the presence of…

Mesoscale and Nanoscale Physics · Physics 2017-07-28 D. B. Szombati , S. Nadj-Perge , D. Car , S. R. Plissard , E. P. A. M. Bakkers , L. P. Kouwenhoven

This paper studies the physics of junctions containing superconducting $(S)$ and normal $(N)$ leads weakly coupled to an Anderson impurity in the Kondo regime $(K)$. Special attention is devoted to the case where one of the leads is a…

Strongly Correlated Electrons · Physics 2009-11-07 T. Aono , A. Golub , Y. Avishai

A stationary Josephson effect in point contacts between triplet superconductors is analyzed theoretically for most probable models of the order parameter in UPt_{3} and Sr_{2}RuO_{4}. The consequence of misorientation of crystals in…

Superconductivity · Physics 2011-07-26 R. Mahmoodi , S. N. Shevchenko , Yu. A. Kolesnichenko

We investigate the dependence of the ground state of a multi-level quantum dot on the coupling to an external fermionic system and on the interactions in the dot. As the coupling to the external system increases, the rearrangement of the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. L. Chudnovskiy , S. E. Ulloa

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

When individual quantum spins are placed in close proximity to conducting substrates, the localized spin is coupled to the nearby itinerant conduction electrons via Kondo exchange. In the strong coupling limit this can result in the Kondo…

Mesoscale and Nanoscale Physics · Physics 2014-11-04 F. Delgado , C. F. Hirjibehedin , J. Fernandez-Rossier

The Josephson transport and the electronic properties of a quantum dot characterized by a single level coupled to superconducting leads is analyzed. Different approximations are used and compared: the mean field approximation, the second…

Condensed Matter · Physics 2009-11-07 E. Vecino , A. Martin-Rodero , A. Levy Yeyati

We study the transmission through a double quantum-dot system in the Kondo regime. An exact expression for the transmission coefficient in terms of fully interacting many-body Green's functions is obtained. By mapping the system into an…

Mesoscale and Nanoscale Physics · Physics 2009-09-29 Luis G. Dias da Silva , Nancy Sandler , Kevin Ingersent , Sergio E. Ulloa

We measure the non-dissipative supercurrent in a single InAs self-assembled quantum dot (QD) coupled to superconducting leads. The QD occupation is both tuned by a back-gate electrode and lateral side-gate. The geometry of the side-gate…

Mesoscale and Nanoscale Physics · Physics 2010-09-30 Y. Kanai , R. S. Deacon , A. Oiwa , K. Yoshida , K. Shibata , K. Hirakawa , S. Tarucha