Kondo effect in spin-orbit mesoscopic interferometers

Lim, Jong Soo; Crişan, M.; Sánchez, David; López, Rosa; Grosu, I.

doi:10.1103/physrevb.81.235309

Cited by 24 publications

(28 citation statements)

References 40 publications

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“…Recently, similar effective fields have been analyzed in spin-orbit quantum dots inserted in Aharanov-Bohm interferometers. 34,35 In these cases, the Kondo resonance can be restored by applying an appropriate external magnetic field B which fullfils the condition B eff + B = 0. In our nanotube system attached to ferromagnetic contacts, spin, orbital and Kramers polarizations are present.…”

Section: Effective Fieldsmentioning

confidence: 99%

Kramers polarization in strongly correlated carbon nanotube quantum dots

et al. 2011

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Ferromagnetic contacts put in proximity with carbon nanotubes induce spin and orbital polarizations. These polarizations affect dramatically the Kondo correlations occurring in quantum dots formed in a carbon nanotube, inducing effective fields in both spin and orbital sectors. As a consequence, the carbon nanotube quantum dot spectral density shows a fourfold split SU(4) Kondo resonance. Furthermore, the presence of spin-orbit interactions leads to the occurrence of an additional polarization among time-reversal electronic states (polarization in the time-reversal symmetry or Kramers sector). Here, we estimate the magnitude for the Kramer polarization in realistic carbon nanotube samples and find that its contribution is comparable to the spin and orbital polarizations. The Kramers polarization generates a new type of effective field that affects only the time-reversal electronic states. We report new splittings of the Kondo resonance in the dot spectral density which can be understood only if Kramers polarization is taken into account. Importantly, we predict that the existence of Kramers polarization can be experimentally detected by performing nonlinear differential conductance measurements. We also find that, due to the high symmetry required to build SU(4) Kondo correlations, its restoration by applying an external field is not possible in contrast to the compensated SU(2) Kondo state observed in conventional quantum dots.

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Section: Effective Fieldsmentioning

confidence: 99%

Kramers polarization in strongly correlated carbon nanotube quantum dots

et al. 2011

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“…The linear conductance is proportional to the transmission probability at the Fermi energy according to Eq. (11). At w R ¼0, the transmission probabilities for the two spin components, which are the same, and have a dip around the Fermi energy due to the interference effect.…”

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confidence: 95%

“…Hence, the RSO interaction makes the quantum transport phenomena rich and complicated [9]. Recently, Vernek et al [10] theoretically predicted that the combination of RSO interaction and the Aharonov-Bohm (AB) effect strongly suppresses the Kondo resonance, and Lim et al [11] found …”

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confidence: 98%

“…To study the Kondo effect of QD analytically, using the well-known impurity Anderson model, many numerical analytical methods have been developed, such as, the second-order perturbation theory [12], the slave-boson mean-field approximation (SBMFA) [13], and the numerical renormalization group (NRG) method [11]. The Anderson model has been extensively studied for more than 40 years [14].…”

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Kondo effect in a double quantum dot interferometer with Rashba spin–orbit interaction

Liu

Yin

Wan

et al. 2011

Physica Status Solidi (b)

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Electronic transport through a double quantum dot interferometer with Rashba spin-orbit interaction is investigated. By means of the slave-boson mean-field approximation and Green function technique, we calculated the local density of states (DOS) and the linear conductance in the Kondo regime at zero temperature. It is shown that the local DOS and the linear conductance of each spin component can be tuned by the Rashba spin-orbit interaction with help of the magnetic flux. In particular, by modulating the strength of the Rashba spin-orbit interaction properly, only one spin component electron can be allowed to transport through this structure. 1 Introduction The Kondo effect in artificial quantum dots (QD) was predicted theoretically more than two decades ago [1,2]. The phenomenon in QD occurs because of a strong antiferromagnetic coupling between the localized spin in the QD and the conduction band electrons in the electrodes through higher-order tunneling processes. The resulting correlated motion gives rise to a Kondo singularity in the density of states (DOS) at the Fermi level and the enhanced conductance. The Kondo effect in the coupled QD has attracted much attention both experimentally and theoretically [3][4][5], recently. The flexibility in tuning various parameters of coupled quantum dos has enabled the study of Kondo phenomena in great detail.In addition, the Rashba spin-orbit (RSO) interaction is an important mechanism that influences the electron-spin state in low-dimensional structures [6][7][8]. The RSO interaction comes into play by introducing an electric field that destroys the symmetry of space inversion in an arbitrary spatial direction. In QD structures, the RSO interaction give rises to an extra spin-dependent phase factor in the coupling matrix elements between the leads and the QD and the inter-level spin-flip term [10]. Hence, the RSO interaction makes the quantum transport phenomena rich and complicated [9]. Recently, Vernek et al. [10] theoretically predicted that the combination of RSO interaction and the Aharonov-Bohm (AB) effect strongly suppresses the Kondo resonance, and Lim et al. [11] found

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“…The Onsager-Casimir 6 symmetry G(B) = G(−B) 7 does not hold for the non-linear transport, 8 where a finite energy window participates in the current flow. Asymmetry of conductance by the non-linear currents carried by the electron gas was studied both experimentally 9-15 and theoretically 8,[16][17][18][19][20][21][22][23][24] in a number of papers.…”

Section: Introductionmentioning

confidence: 99%

Carrier-carrier inelastic scattering events for spatially separated electrons: Magnetic asymmetry and turnstile electron transfer

Poniedziałek

Szafran

2012

Phys. Rev. B

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We consider a single electron traveling along a strictly one-dimensional quantum wire interacting with another electron in a quantum ring capacitively coupled to the wire. We develop an exact numerical method for treating the scattering problem within the stationary two-electron wave function picture. The considered process conserves the total energy but the electron within the wire passes a part of its energy to the ring. We demonstrate that the inelastic scattering results in both magnetic asymmetry of the transfer probability and a turnstile action of the ring on the electrons traveling separately along the ring. We demonstrate that the inelastic backscattering and / or inelastic electron transfer can be selectively eliminated from the process by inclusion of an energy filter into the wire in form of a double barrier system with the resonant energy level tuned to the energy of the incident electron. We demonstrate that the magnetic symmetry is restored when the inelastic backscattering is switched off, and the turnstile character of the ring is removed when the energy transfer to the ring is excluded for both transferred and backscattered electron waves. We discuss the relation of the present results to the conductance systems based on the electron gas.

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Kondo effect in spin-orbit mesoscopic interferometers

Cited by 24 publications

References 40 publications

Kramers polarization in strongly correlated carbon nanotube quantum dots

Kramers polarization in strongly correlated carbon nanotube quantum dots

Kondo effect in a double quantum dot interferometer with Rashba spin–orbit interaction

Carrier-carrier inelastic scattering events for spatially separated electrons: Magnetic asymmetry and turnstile electron transfer

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