Two-electron bunching in transport through a quantum dot induced by Kondo correlations

Abstract

We report on noise measurements in a quantum dot in the presence of Kondo correlations. Close to the unitary limit, with the conductance reaching 1.8e2 /h, we observed an average backscattered charge of e*~5e/3, while weakly biasing the quantum dot. This result held to bias voltages up to half the Kondo temperature.Away from the unitary limit, the charge was measured to be e as expected. These results confirm and extend the prediction by E. Sela et al. [1], that suggested that twoelectron backscattering processes dominate over single-electron backscattering processes near the unitary limit, with an average backscattered charge e*~5e/3.

Shot Noise as a Probe of Spin-Polarized Transport through Single Atoms

“…Third, the similarly reduced noise for Co needs to be reconciled with the fact that Co displays a Kondo effect. Publications on the influence of the Kondo effect on shot noise are rare [26][27][28]. In general, a Kondo signature in the dI=dV spectra does not imply that the impurity spin is completely screened.…”

Universality of non-equilibrium fluctuations in strongly correlated quantum liquids

“…This value, closely related to the Wilson ratio, is universal for the Fermi liquid in the Kondo regime as it depends only on the symmetry group of the system [13][14][15] . Although some aspects of Kondo-associated noise have been reported 8,16,17 , a rigorous, selfconsistent treatment in a regime where universal results apply is at the core of the present work. Actually, by investigating the same nanotube quantum dot in the spin degenerate SU(2) Kondo regime and in the spin-orbit degenerate SU(4) regime, the noise is proved to contain distinct signatures of these two symmetries, confirming theoretical developments of Fermi liquid theory out of equilibrium.…”

“…, an enhancement of the current fluctuations is detected out of equilibrium and perfectly explained by an e ective charge induced by the residual interaction between quasi-particles 8, [10][11][12][13][14][15][16][17] . Moreover, an as-yet-unknown scaling law for the e ective charge is discovered, suggesting a new non-equilibrium universality.…”

Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts

“…Since this theory is based on the single-particle picture, additional information such as the many-body interaction may be deduced from the precise investigation of the Fano factor combined with the conductance, as we see in the shot noise study in the Kondo regime [19][20][21][22] . Actually, the shot noise of QPC was addressed by several experimental groups; the Pauli exclusion principle was first studied, and then the quantum interference 23 , the 0.7 anomaly [24][25][26] , and the spin polarization 25,27 .…”