The Kondo Effect in Mesoscopic Quantum Dots

Grobis, M.; Rau, I. G.; Potok, R. M.; Goldhaber‐Gordon, David

doi:10.1002/9780470022184.hmm523

Cited by 51 publications

(37 citation statements)

References 138 publications

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“…If the electron spin is taken into account, one can encounter another elastic cotunneling process connected to the Kondo effect [31][32][33][34][35][36][37][38][39]. Whenever a single localized state in the molecule is spin-degenerate and partially filled, the molecule has a net spin (magnetic moment).…”

Section: Intermediate Coupling: Cotunneling and Kondo Effectmentioning

confidence: 99%

Single-molecule transport in three-terminal devices

Osorio

Bjørnholm

Lehn

et al. 2008

J. Phys.: Condens. Matter

103

114

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Transport through single molecules has been studied using different test beds. In this paper we focus on three-terminal devices in which a molecule bridges the gap between two gold electrodes and a third electrode-the gate-is able to modulate the conduction properties of the junction. Depending on the electronic coupling, , between the molecule and the gold electrodes, different transport regimes can be distinguished. We show measurements on junctions incorporating different single-molecule systems which demonstrate the distinction between these regimes, as well as the experimental limitations in controlling the exact value of .

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Section: Intermediate Coupling: Cotunneling and Kondo Effectmentioning

confidence: 99%

Single-molecule transport in three-terminal devices

Osorio

Bjørnholm

Lehn

et al. 2008

J. Phys.: Condens. Matter

103

114

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“…Other scales, such as the charging energy U C or lead coupling Γ, can be an order of magnitude larger, yet to describe the response to external parameters we require only T K and G 0 , the zero temperature conductance. Under influence of a finite temperature, bias voltage or magnetic field (X = k B T , eV SD or gµ B B) the normalized conductance G(X)/G 0 is reduced monotonically from unity following a curve that scales only with X/k B T K [6]. Once appropriately scaled the behavior of any microscopic realization of the Kondo model can be collapsed onto this curve.…”

mentioning

confidence: 99%

Kondo Universal Scaling for a Quantum Dot Coupled to Superconducting Leads

et al. 2007

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We study competition between the Kondo effect and superconductivity in a single self-assembled InAs quantum dot contacted with Al lateral electrodes. Due to Kondo enhancement of Andreev reflections the zero-bias anomaly develops sidepeaks, separated by the superconducting gap energy ∆. For ten valleys of different Kondo temperature TK we tune the gap ∆ with an external magnetic field. We find that the zero-bias conductance in each case collapses onto a single curve with ∆/kBTK as the only relevant energy scale, providing experimental evidence for universal scaling in this system.

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“…In the case of an S = 1/2 impurity such anisotropic behaviour due to crystal-field effects is expected to be absent. We note that the precise nature of the splitting of the Kondo peak, especially for magnetic fields that are small compared to the Kondo temperature, is still under theoretical debate 23,24,26 .…”

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confidence: 99%

The role of magnetic anisotropy in the Kondo effect

et al. 2008

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In the Kondo effect, a localized magnetic moment is screened by forming a correlated electron system with the surrounding conduction electrons of a non-magnetic host 1 . Spin S = 1/2 Kondo systems have been investigated extensively in theory and experiments, but magnetic atoms often have a larger spin 2 . Larger spins are subject to the influence of magnetocrystalline anisotropy, which describes the dependence of the magnetic moment's energy on the orientation of the spin relative to its surrounding atomic environment 3,4 . Here we demonstrate the decisive role of magnetic anisotropy in the physics of Kondo screening. A scanning tunnelling microscope is used to simultaneously determine the magnitude of the spin, the magnetic anisotropy and the Kondo properties of individual magnetic atoms on a surface. We find that a Kondo resonance emerges for large-spin atoms only when the magnetic anisotropy creates degenerate ground-state levels that are connected by the spin flip of a screening electron. The magnetic anisotropy also determines how the Kondo resonance evolves in a magnetic field: the resonance peak splits at rates that are strongly direction dependent. These rates are well described by the energies of the underlying unscreened spin states.A low density of magnetic impurities in a non-magnetic host metal can have dramatic effects on the magnetic, thermodynamic and electrical properties of the material owing to the Kondo effect, a many-body interaction between the metal's conduction electrons and the electron spin of the localized magnetic impurity 5 . This interaction gives rise to a narrow, pronounced peak in the density of states close to the Fermi energy 1 . The past decade has seen a surge of interest in the Kondo screening of individual atomic spins, as a result of experimental advances in probing individual magnetic atoms by using scanning tunnelling microscopes 6,7 and single-molecule transistors 8,9 . When magnetic atoms are placed on metal surfaces the Kondo interaction between the localized spin and the conduction electrons is very strong, leading to high Kondo temperatures T K , in the range from 40 to 200 K (ref. 10). In order to probe the Kondo physics it is desirable to reduce this interaction so that the Kondo screening competes on an equal footing with external influences such as magnetic fields. It was shown recently that this can be achieved by incorporating a decoupling layer between the atomic spin and the screening conduction electrons 11 .

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The Kondo Effect in Mesoscopic Quantum Dots

Cited by 51 publications

References 138 publications

Single-molecule transport in three-terminal devices

Single-molecule transport in three-terminal devices

Kondo Universal Scaling for a Quantum Dot Coupled to Superconducting Leads

The role of magnetic anisotropy in the Kondo effect

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