Shot noise and Coulomb effects on nonlocal electron transport in normal-metal/superconductor/normal-metal heterostructures

Golubev, Dmitri S.; Zaikin, Andrei D.

doi:10.1103/physrevb.82.134508

Cited by 22 publications

(19 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Ref. 30, a quasiclassical analysis using a perturbative expansion in the nonlocal Green's function connecting the two interfaces led to positive noise correlations at high transparencies, and the authors conclude that it is due to CAR. This interpretation looks surprising, given the domination of EC in the conductance in the same regime, and the total absence of CAR at high transparency in the transmission coefficient.…”

Section: Introductionmentioning

confidence: 96%

Absence of split pairs in cross correlations of a highly transparent normal metal–superconductor–normal metal electron-beam splitter

2013

View full text Add to dashboard Cite

The nonlocal conductance and the current cross-correlations are investigated within scattering theory for threeterminal normal metal-superconductor-normal metal (NSN) hybrid structures. The positive cross-correlations at high transparency found by Mélin, Benjamin, and Martin [Phys. Rev. B 77, 094512 (2008)] are not due to crossed Andreev reflection. On the other hand, local processes can be enhanced by reflectionless tunneling but this mechanism has little influence on nonlocal processes and on current cross-correlations. Therefore Cooper pair splitting cannot be enhanced by reflectionless tunneling. Overall, this shows that NSN structures with highly transparent or effectively highly transparent interfaces are not suited to experimentally producing entangled split pairs of electrons.

show abstract

Section: Introductionmentioning

confidence: 96%

Absence of split pairs in cross correlations of a highly transparent normal metal–superconductor–normal metal electron-beam splitter

2013

View full text Add to dashboard Cite

show abstract

“…26,27 Recently the effect of Coulomb interaction has been studied in some of these systems. 28,29 On the experimental side, noise experiments with normal superconducting devices constitute a real challenge. A successful experiment demonstrated that the Fano factor of a single NS junction is 2, corresponding to the charge of a Cooper pair.…”

Section: Introductionmentioning

confidence: 99%

Current and noise correlations in a double-dot Cooper-pair beam splitter

et al. 2011

View full text Add to dashboard Cite

We consider a double quantum dot coupled to two normal leads and one superconducting lead, modeling the Cooper pair beam splitter studied in two recent experiments. Starting from a microscopic Hamiltonian we derive a general expression for the branching current and the noise crossed correlations in terms of a single-and two-particle Green's function of the dot electrons. We then study numerically how these quantities depend on the energy configuration of the dots and the presence of direct tunneling between them, isolating the various processes which come into play. In the absence of direct tunneling, the antisymmetric case (the two levels have opposite energies with respect to the superconducting chemical potential) optimizes the crossed Andreev reflection (CAR) process while the symmetric case (the two levels have the same energies) favors the elastic cotunneling (EC) process. Switching on the direct tunneling tends to suppress the CAR process, leading to negative noise crossed correlations over the whole voltage range for large enough direct tunneling.

show abstract

“…(13) This in turn allows us to write the full vertex functionˇ by self-consistently solving the Bethe-Salpeter equation in the corresponding irreducibility channel [see Fig. 1(b)]:…”

Section: Kadanoff-baym-keldysh Formalismmentioning

confidence: 99%

“…[7][8][9] Several theoretical works have suggested different directions in order to provide preferential enhancement of CAR, from simple spin and energy filtering to the effect of strong electron interactions, susceptible to favor single-particle over pair tunneling. [10][11][12][13][14] An important step in the observation of Cooper-pair splitting came from recent experimental works in tunable double quantum dot devices based on carbon nanotubes 15 and InAs nanowires. 16 These systems showed great promise, as they not only display local Coulomb repulsion on the dots, but also allow for the exploration of different energy configurations of the dots, two properties that should promote CAR over other processes.…”

Section: Introductionmentioning

confidence: 99%

Current correlations in an interacting Cooper-pair beam splitter

Rech

Chevallier²,

Jonckheere³

et al. 2012

Phys. Rev. B

View full text Add to dashboard Cite

We propose an approach allowing the computation of currents and their correlations in interacting multiterminal mesoscopic systems involving quantum dots coupled to normal and/or superconducting leads. The formalism relies on the expression of branching currents and noise crossed correlations in terms of one-and two-particle Green's functions for the dots electrons, which are then evaluated self-consistently within a conserving approximation. We then apply this to the Cooper-pair beam-splitter setup recently proposed [L. Hofstetter et al., Nature (London) 461, 960 (2009); Phys. Rev. Lett. 107, 136801 (2011); L. G. Herrmann et al., ibid. 104, 026801 (2010)], which we model as a double quantum dot with weak interactions, connected to a superconducting lead and two normal ones. Our method not only enables us to take into account a local repulsive interaction on the dots, but also to study its competition with the direct tunneling between dots. Our results suggest that even a weak Coulomb repulsion tends to favor positive current cross correlations in the antisymmetric regime (where the dots have opposite energies with respect to the superconducting chemical potential).

show abstract

Shot noise and Coulomb effects on nonlocal electron transport in normal-metal/superconductor/normal-metal heterostructures

Cited by 22 publications

References 34 publications

Absence of split pairs in cross correlations of a highly transparent normal metal–superconductor–normal metal electron-beam splitter

Absence of split pairs in cross correlations of a highly transparent normal metal–superconductor–normal metal electron-beam splitter

Current and noise correlations in a double-dot Cooper-pair beam splitter

Current correlations in an interacting Cooper-pair beam splitter

Contact Info

Product

Resources

About