Observation of the Kondo screening cloud

Borzenets, Ivan; Shim, Jeongmin; Chen, Jason C. H.; Ludwig, Arne; Wieck, A. D.; Tarucha, Seigo; Sim, Hyun Sub; Yamamoto, Mahito

doi:10.1038/s41586-020-2058-6

Cited by 82 publications

(57 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The screening cloud around the impurity spreads over a sizable distance and serves as a scattering center for the conduction electrons. Recently, the size of the Kondo cloud was directly measured for a quantum dot immersed in a quasi 1D channel [ 4 ] and found to be of the order of micrometer at very small temperatures,

T ≪ T_{normalK}

. As the size, and thus the scattering phase shift, of the screening cloud decreases as a function of temperature T , the resistivity decreases from its value at zero temperature before it eventually increases again due to electron–phonon scattering.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics and Screening in the Ising–Kondo Model

Bauerbach

Mahmoud

Gebhard

2020

Physica Status Solidi (b)

View full text Add to dashboard Cite

A simplification of the symmetric single‐impurity Kondo model is introduced and studied. In the Ising–Kondo model, host electrons scatter off a single magnetic impurity at the origin whose spin orientation is dynamically conserved. This reduces the problem to potential scattering of spinless fermions that can be solved exactly using the equation‐of‐motion technique. The Ising–Kondo model provides an example for static screening. At low temperatures, the thermodynamics at finite magnetic fields resembles that of a free spin‐1/2 in a reduced external field. Alternatively, the Curie law is interpreted in terms of an antiferromagnetically screened effective spin. The spin correlations decay algebraically to zero in the ground state and display commensurate Friedel oscillations. In contrast to the symmetric Kondo model, the impurity spin is not completely screened, i.e., the screening cloud contains less than a spin‐1/2 electron. At finite temperatures and weak interactions, the spin correlations decay to zero exponentially with correlation length ξ(T) = 1/(2πT).

show abstract

T ≪ T_{normalK}

Section: Introductionmentioning

confidence: 99%

Thermodynamics and Screening in the Ising–Kondo Model

Bauerbach

Mahmoud

Gebhard

2020

Physica Status Solidi (b)

View full text Add to dashboard Cite

show abstract

“…It is responsible for increasing the local density of states and leads to the Abrikosov-Suhl resonance [118], which causes the increase, below T K , of the dot conductance in Coulomb blockaded regimes [93,119,120]. Remarkably, the Kondo phase-shift δ K = π/2 and the Kondo screening cloud have been also directly observed in two recent distinct experiments [121,122]. In Section 4.7, we illustrate how such phenomena also affect the dynamical properties of the mesoscopic capacitor in a non-trivial way.…”

Section: Anderson Impurity Modelmentioning

confidence: 80%

Phase-Coherent Dynamics of Quantum Devices with Local Interactions

Filippone

Marguerite

Hur

et al. 2020

Entropy

View full text Add to dashboard Cite

This review illustrates how Local Fermi Liquid (LFL) theories describe the strongly correlated and coherent low-energy dynamics of quantum dot devices. This approach consists in an effective elastic scattering theory, accounting exactly for strong correlations. Here, we focus on the mesoscopic capacitor and recent experiments achieving a Coulomb-induced quantum state transfer. Extending to out-of-equilibrium regimes, aimed at triggered single electron emission, we illustrate how inelastic effects become crucial, requiring approaches beyond LFLs, shedding new light on past experimental data by showing clear interaction effects in the dynamics of mesoscopic capacitors.

show abstract

“…Some of the clearest and most controlled spectroscopic observations of the Kondo effect [42,43], as well as demonstrations of the size of the associated cloud [44], are obtained in mesoscopic transport experiments. Here, the impurity embedded in a metallic host is replaced by a quantum dot spanning two noninteracting leads.…”

Section: Introductionmentioning

confidence: 99%

Resolving the nonequilibrium Kondo singlet in energy- and position-space using quantum measurements

Erpenbeck

Cohen

2021

SciPost Phys.

View full text Add to dashboard Cite

The Kondo effect, a hallmark of strong correlation physics, is characterized by the formation of an extended cloud of singlet states around magnetic impurities at low temperatures. While many implications of the Kondo cloud's existence have been verified, the existence of the singlet cloud itself has not been directly demonstrated. We suggest a route for such a demonstration by considering an observable that has no classical analog, but is still experimentally measurable: ``singlet weights'', or projections onto particular entangled two-particle states. Using approximate theoretical arguments, we show that it is possible to construct highly specific energy- and position-resolved probes of Kondo correlations. Furthermore, we consider a quantum transport setup that can be driven away from equilibrium by a bias voltage. There, we show that singlet weights are enhanced by voltage even as the Kondo effect is weakened by it. This exposes a patently nonequilibrium mechanism for the generation of Kondo-like entanglement that is inherently different from its equilibrium counterpart.

show abstract

Observation of the Kondo screening cloud

Cited by 82 publications

References 34 publications

Thermodynamics and Screening in the Ising–Kondo Model

Thermodynamics and Screening in the Ising–Kondo Model

Phase-Coherent Dynamics of Quantum Devices with Local Interactions

Resolving the nonequilibrium Kondo singlet in energy- and position-space using quantum measurements

Contact Info

Product

Resources

About