From Coulomb blockade to the Kondo regime in a Rashba dot

López, Rosa; Sánchez, David; Serra, Llorenç

doi:10.1103/physrevb.76.035307

Cited by 48 publications

(46 citation statements)

References 36 publications

(38 reference statements)

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“…In fact, for ballistic wires without Rashba coupling but multiple populated subbands, a simple mean-field approach demonstrates 68 that Coulomb interactions are crucial to an understanding of rectification effects observed in nanojunction rectifiers. 69 On the other hand, single-particle effects are shown 53 to lead to Coulomb blockade antiresonances of the Fano form. Hence, further work is needed to clarify the influence of Coulomb interactions in the conductance of a quantum wire with Zeeman splitting and a localized Rashba interaction.…”

Section: Discussionmentioning

confidence: 99%

“…30 Interestingly, when charging effects are taken into account, Coulomb blockade resonances can be tuned, directly modulating the strength of the Rashba coupling. 53 A magnetic field applied in the wire plane leads to Zeeman spin splitting of the 1D modes. Evidence of this is seen in the appearance of conductance plateaus at odd multiples of e 2 / h. 40 In the first plateau, the current is fully polarized since only one spin species is allowed to propagate.…”

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confidence: 99%

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Strongly modulated transmission of a spin-split quantum wire with local Rashba interaction

2008

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We investigate the transport properties of ballistic quantum wires in the presence of Zeeman spin splittings and a spatially inhomogeneous Rashba interaction. The Zeeman interaction is extended along the wire and produces gaps in the energy spectrum, which allow electron propagation only for spinors lying along a certain direction. For spins in the opposite direction, the waves are evanescent far away from the Rashba region, which plays the role of the scattering center. The most interesting case occurs when the magnetic field is perpendicular to the Rashba field. Then, the spins of the asymptotic wave functions are not eigenfunctions of the Rashba Hamiltonian, and the resulting coupling between spins in the Rashba region gives rise to sudden changes of the transmission probability when the Fermi energy is swept along the gap. After briefly examining the energy spectrum and eigenfunctions of a wire with extended Rashba coupling, we analyze the transmission through a region of localized Rashba interaction, in which a double interface separates a region of constant Rashba interaction from wire leads free from spin-orbit coupling. For energies slightly above the propagation threshold, we find the ubiquitous occurrence of transmission zeros ͑antiresonances͒, which are analyzed by matching methods in the one-dimensional limit. We find that a minimal tight-binding model yields analytical transmission line shapes of Fano antiresonance type. The general angular dependence of the external magnetic field is treated within projected Schrödinger equations with the nondiagonal Hamiltonian matrix elements mixing different wave function components. Finally, we consider a realistic quantum wire where the energy subbands are coupled via the Rashba intersubband coupling term and discuss its effect on the transmission zeros. We find that the antiresonances are robust against intersubband mixing, magnetic field changes, and smooth variations of the wire interfaces, which paves the way for possible applications of spin-split Rashba wires as spintronic current modulators.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Strongly modulated transmission of a spin-split quantum wire with local Rashba interaction

2008

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“…7 Since both the level position and broadening can be tuned with the Rashba strength ␣, these states are termed Rashba dots. 6 Recently, López et al 8 formulated a microscopic theory for transport across Rashba dots including Coulomb interactions in the dot. An important aspect of this model is that different regimes can be achieved by tuning the parameters of the Rashba Hamiltonian, and this can be done by modulating external electric fields applied to nearby gates.…”

Section: Introductionmentioning

confidence: 99%

“…10 Remarkably, despite these differences the system shows a persisting Kondo effect at low temperatures but with a novel gate dependence. 8 In this paper, we address the magnetic properties of Rashba dots. We follow Anderson's model for magnetic impurities in a metallic host and determine whether it is energetically favorable for the dot to form a localized magnetic moment.…”

Section: Introductionmentioning

confidence: 99%

Localized magnetic states in Rashba dots

et al. 2009

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We study the formation of local moments in quantum dots arising in quasi-one-dimensional electron wires due to localized spin-orbit ͑Rashba͒ interaction. Using an Anderson-type model to describe the occurrence of the magnetic moments in these Rashba dots, we calculate the local magnetization within the mean-field approximation. We find that the magnetization becomes a nontrivial function of the Rashba coupling strength. We discuss both the equilibrium and nonequilibrium cases. Interestingly, we obtain a magnetic phase which is stable at large bias due to the Rashba interaction.

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“…In a similar quantum wire configuration but with the Rashba coupling restricted to a finite region of the wire, recent works showed the importance of the mixing term in the modulation of the conductance. [12][13][14][15][16] These modulations are examples of Fano resonances due to the coupling with quasi bound states. Since this behavior is caused by the spinorbit coupling alone it has been called the Fano-Rashba effect.…”

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Conductance oscillations of a spin-orbit stripe with polarized contacts

Gelabert

Serra

2011

Eur. Phys. J. B

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We investigate the linear conductance of a stripe of spin-orbit interaction in a 2D electron gas; that is, a 2D region of length ℓ along the transport direction and infinite in the transverse one in which a spin-orbit interaction of Rashba type is present. Polarization in the contacts is described by means of Zeeman fields. Our model predicts two types of conductance oscillations: Ramsauer oscillations in the minority spin transmission, when both spins can propagate, and Fano oscillations when only one spin propagates. The latter are due to the spin-orbit coupling with quasibound states of the non propagating spin. In the case of polarized contacts in antiparallel configuration Fano-like oscillations of the conductance are still made possible by the spin orbit coupling, even though no spin component is bound by the contacts. To describe these behaviors we propose a simplified model based on an ansatz wave function. In general, we find that the contribution for vanishing transverse momentum dominates and defines the conductance oscillations. Regarding the oscillations with Rashba coupling intensity, our model confirms the spin transistor behavior, but only for high degrees of polarization. Including a position dependent effective mass yields additional oscillations due to the mass jumps at the interfaces.

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From Coulomb blockade to the Kondo regime in a Rashba dot

Cited by 48 publications

References 36 publications

Strongly modulated transmission of a spin-split quantum wire with local Rashba interaction

Strongly modulated transmission of a spin-split quantum wire with local Rashba interaction

Localized magnetic states in Rashba dots

Conductance oscillations of a spin-orbit stripe with polarized contacts

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