Bias-controllable intrinsic spin polarization in a quantum dot: Proposed scheme based on spin-orbit interaction

Sun, Qing-Feng; Xie, X. C.

doi:10.1103/physrevb.73.235301

Cited by 128 publications

(46 citation statements)

References 34 publications

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“…According to [26,27], the spin-dependent phase factor φ R due to the RSOI can be expressed as

(φ_{normalR} = φ_{normalR 1} - φ_{normal R 2} = β m^{*} false(L_{1} - L_{2} false) false/ ℏ^{2})

, where β is the RSOI strength, m ∗ is the electron effective mass, and L i is the length of dot i. φ R is tunable in experiments. It can reach Π /2 easily or can be larger experimentally [27].…”

Section: Resultsmentioning

confidence: 99%

“…The RSOI results from a relativistic effect at the low speed limit, and it can couple the electron spin to its orbital motion, thus providing a possible way to control the spin degree of freedom by means of an external electric field. As a consequence, the coherent indirect coupling and the RSOI make the quantum transport through the QD systems rich and varied [26-30]. …”

Section: Introductionmentioning

confidence: 99%

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Tunable spin-dependent Andreev reflection in a four-terminal Aharonov-Bohm interferometer with coherent indirect coupling and Rashba spin-orbit interaction

2012

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Using the nonequilibrium Green’s function method, we theoretically study the Andreev reflection(AR) in a four-terminal Aharonov-Bohm interferometer containing a coupled double quantum dot with the Rashba spin-orbit interaction (RSOI) and the coherent indirect coupling via two ferromagnetic leads. When two ferromagnetic electrodes are in the parallel configuration, the spin-up conductance is equal to the spin-down conductance due to the absence of the RSOI. However, for the antiparallel alignment, the spin-polarized AR occurs resulting from the crossed AR (CAR) and the RSOI. The effects of the coherent indirect coupling, RSOI, and magnetic flux on the Andreev-reflected tunneling magnetoresistance are analyzed at length. The spin-related current is calculated, and a distinct swap effect emerges. Furthermore, the pure spin current can be generated due to the CAR when two ferromagnets become two half metals. It is found that the strong RSOI and the large indirect coupling are in favor of the CAR and the production of the strong spin current. The properties of the spin-related current are tunable in terms of the external parameters. Our results offer new ways to manipulate the spin-dependent transport.

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“…According to [26,27], the spin-dependent phase factor φ R due to the RSOI can be expressed as

(φ_{normalR} = φ_{normalR 1} - φ_{normal R 2} = β m^{*} false(L_{1} - L_{2} false) false/ ℏ^{2})

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tunable spin-dependent Andreev reflection in a four-terminal Aharonov-Bohm interferometer with coherent indirect coupling and Rashba spin-orbit interaction

2012

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“…When the RSOI is considered, the spin-dependent quantum interference in the device can be expected. If one only considers the lowestorder tunneling processes in this device, the spin-dependent effective tunnel coupling strengths between the hot and two cold electrodes can be expressed as 30,31 …”

Section: Resultsmentioning

confidence: 99%

A single-spin-current thermal generator

Liu

Yang

Hong

et al. 2012

Journal of Applied Physics

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We theoretically propose a single-spin-current thermal generator consisting of a Rashba quantum dot (QD), one hot electrode and two cold electrodes. The Rashba QD is directly coupled to the three electrodes, and there exists a bridge channel between the two cold electrodes. Our results show the QD device can be used to generate pure spin-up or spin-down currents in cold electrodes in the absence of bias voltages and magnetic materials. The underlying reason is a cooperative effect of the spin-dependent quantum interference effects originating from Rashba spin-orbit interaction in the QD and temperature gradients among the three electrodes. The working conditions for the single-spin-current thermal generator are also clearly presented. Moreover, we also find that the device can be converted from n-type to p-type or vice versa by a gate voltage. V C 2012 American Institute of Physics. [http://dx.

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“…[15][16][17][18] When a dot subject to Rashba interaction is embedded in the mesoscopic interferometer, the traveling electrons acquire a spin-dependent phase in addition to the Aharonov-Bohm phase. 19 A similar effect takes place in quantum wires with localized Rashba coupling, 20 in which case localized magnetic states can be formed in nonequilibrium situations. 21 For spin-orbit quantum-dot Aharonov-Bohm systems, the spin polarization can be controlled by tuning the magnetic flux and the Rashba strength.…”

Section: Introductionmentioning

confidence: 86%

Kondo effect in spin-orbit mesoscopic interferometers

et al. 2010

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We consider a flux-threaded Aharonov-Bohm ring with an embedded quantum dot coupled to two normal leads. The local Rashba spin-orbit interaction acting on the dot electrons leads to a spin-dependent phase factor in addition to the Aharonov-Bohm phase caused by the external flux. Using the numerical renormalization group method, we find a splitting of the Kondo resonance at the Fermi level which can be compensated by an external magnetic field. To fully understand the nature of this compensation effect, we perform a scaling analysis and derive an expression for the effective magnetic field. The analysis is based on a tight-binding model which leads to an effective Anderson model with a spin-dependent density of states for the transformed lead states. We find that the effective field originates from the combined effect of Rashba interaction and magnetic flux and that it contains important corrections due to electron-electron interactions. We show that the compensating field is an oscillatory function of both the spin-orbit and the Aharonov-Bohm phases. Moreover, the effective field never vanishes due to the particle-hole symmetry breaking independently of the gate voltage.Comment: 9 pages, 5 figure

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Bias-controllable intrinsic spin polarization in a quantum dot: Proposed scheme based on spin-orbit interaction

Cited by 128 publications

References 34 publications

Tunable spin-dependent Andreev reflection in a four-terminal Aharonov-Bohm interferometer with coherent indirect coupling and Rashba spin-orbit interaction

Tunable spin-dependent Andreev reflection in a four-terminal Aharonov-Bohm interferometer with coherent indirect coupling and Rashba spin-orbit interaction

A single-spin-current thermal generator

Kondo effect in spin-orbit mesoscopic interferometers

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