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We demonstrate a tunable Kondo effect realized in small quantum dots. We can switch our dot from a Kondo impurity to a non-Kondo system as the number of electrons on the dot is changed from odd to even. We show that the Kondo temperature…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Sara M. Cronenwett , Tjerk H. Oosterkamp , Leo P. Kouwenhoven

Ground-state properties of a double-large-dot sample connected to a reservoir via a single-mode point contact are investigated. When the interdot transmission is perfect and the dots controlled by the same dimensionless gate voltage, we…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Karyn Le Hur

Coupled quantum dots are potential candidates for qubit systems in quantum computing. We use a non-invasive voltage probe to study the evolution of a coupled dot system from a situation where the dots are coupled to the leads to a situation…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. W. Rushforth , C. G. Smith , M. D. Godfrey , H. E. Beere , D. A. Ritchie , M. Pepper

Electrons in a quantum-dot spin valve, consisting of a single-level quantum dot coupled to two ferromagnetic leads with magnetizations pointing in arbitrary directions, experience an exchange field that is induced on the dot by the…

Mesoscale and Nanoscale Physics · Physics 2010-09-24 Björn Sothmann , David Futterer , Michele Governale , Jürgen König

Quantum phase transitions encompass a variety of phenomena that occur in quantum systems exhibiting several possible symmetries. Traditionally, these transitions are explored by continuously varying a control parameter that connects two…

Quantum Physics · Physics 2024-06-12 Á. Sáiz , J. Khalouf-Rivera , J. M. Arias , P. Pérez-Fernández , J. Casado-Pascual

We consider a single-level quantum dot coupled to magnetic insulators (magnonic reservoirs) and magnetic metals (electronic reservoirs). The whole system is in an external magnetic field. In a general case, the system includes two magnonic…

Mesoscale and Nanoscale Physics · Physics 2017-06-20 Łukasz Karwacki , Piotr Trocha , Józef Barnaś

For the last decade, tunable quantum dot systems have allowed the investigation of Kondo physics wherein the quenching of a single spin on an artificial atom affects the conductance. The pseudogap Kondo model featuring a density of states…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 John Hopkinson , Karyn Le Hur , Emilie Dupont

We consider the time-dependent electron transport through a quantum dot connected to multiple leads in the presence of the additional over-dot (bridge) tunnelling channels by using the evolution operator technique. Each terminal and quantum…

Mesoscale and Nanoscale Physics · Physics 2007-06-13 R. Taranko , T. Kwapinski , E. Taranko

We study transport through a quantum dot side-coupled to two parallel Luttinger liquid leads in the presence of a Coulombic dot-lead interaction. This geometry enables an exact treatment of the inter-lead Coulomb interactions. We find that…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Florian Elste , David Reichman , Andrew Millis

We study coupled semiconductor quantum dots theoretically through a generalized Hubbard approach, where intra- and inter-dot Coulomb Correlation, as well as tunneling effects are described on the basis of realistic electron wavefunctions.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Massimo Rontani , F. Rossi , F. Manghi , E. Molinari

We present a systematic study of the role of Anderson orthogonality for the dynamics after a quantum quench in quantum impurity models, using the numerical renormalization group. As shown by Anderson in 1967, the scattering phase shifts of…

Strongly Correlated Electrons · Physics 2013-01-16 Wolfgang Münder , Andreas Weichselbaum , Moshe Goldstein , Yuval Gefen , Jan von Delft

We investigate the transport properties of a (small) quantum dot connected to Fermi liquid leads with a power-law density of states (DOS). Such a system, if experimentally realizable, will have interesting physical properties including: (i)…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 J. Hopkinson , K. Le Hur , E. Dupont

Few-electron systems confined in a quantum dot laterally coupled to a surrounding quantum ring in the presence of an external magnetic field are studied by exact diagonalization. The distribution of electrons between the dot and the ring is…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 B. Szafran , F. M. Peeters , S. Bednarek

We study correlated two-level quantum dots, coupled in effective 1-channel fashion to metallic leads; with electron interactions including on-level and inter-level Coulomb repulsions, as well as the inter-orbital Hund's rule exchange…

Strongly Correlated Electrons · Physics 2009-10-05 David E. Logan , Christopher J. Wright , Martin R. Galpin

We propose a new transport mechanism through tunnel-coupled quantum dots based on the coherent population trapping effect. Coupling to an excited level by the coherent radiation of two microwaves can lead to an extremely narrow current…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 T. Brandes , F. Renzoni

The complex transmission amplitude -- both magnitude and phase -- of a quantum dot (QD) with Kondo correlation was measured near the unitary limit. Contrary to previous phase measurements, performed far from this limit [Ji et al., Science…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Yang Ji , M. Heiblum , Hadas Shtrikman

With non-invasive methods, we investigate ground and excited states of a lateral quantum dot. Charge detection via a quantum point contact is used to map the dot dynamics in a regime where the current through the dot is too low for…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. C. Rogge , B. Harke , C. Fricke , F. Hohls , M. Reinwald , W. Wegscheider , R. J. Haug

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

We measure the magneto-conductance through a micron-sized quantum dot hosting about 500 electrons in the quantum Hall regime. In the Coulomb blockade, when the island is weakly coupled to source and drain contacts, edge reconstruction at…

Transport measurements at cryogenic temperatures through a few electron top gated quantum dot fabricated in a silicon/silicon-germanium heterostructure are reported. Variations in gate voltage induce a transition from an isolated dot toward…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Levente J. Klein , Donald E. Savage , Mark A. Eriksson