Effect of the spin-orbit geometric phase on the spectrum of Aharonov-Bohm oscillations in a semiconductor mesoscopic ring

Mal’shukov, A. G.; Shlyapin, V. V.; Chao, K. A.

doi:10.1103/physrevb.60.r2161

Cited by 33 publications

(26 citation statements)

References 16 publications

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“…Such structures enable an all-electrical control of the spins via the Rashba spin-orbit interaction by changing the gate voltage. [7][8][9][10][11] This spin interference in a semiconductor ring ͑see Fig. 1͒ has been proposed as a way to control spin-polarized currents 12,21 and as a spin filter.…”

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confidence: 99%

Aharonov-Casher effect in a two-dimensional hole ring with spin-orbit interaction

Kovalev

Borunda²,

Jungwirth³

et al. 2007

Phys. Rev. B

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We study the quantum interference effects induced by the Aharonov-Casher phase in a ring structure in a two-dimensional heavy-hole ͑HH͒ system with spin-orbit interaction realizable in narrow asymmetric quantum wells. The influence of the spin-orbit interaction strength on the transport is analytically investigated. These analytical results allow us to explain the interference effects as a signature of the Aharonov-Casher Berry phases. Unlike previous studies on electron two-dimensional Rashba systems, we find that the frequency of conductance modulations as a function of the spin-orbit strength is not constant but increases for larger spin-orbit splittings. In the limit of thin channel rings ͑width smaller than Fermi wavelength͒, we find that the spin-orbit splitting can be greatly increased due to the quantization in the radial direction. We also study the influence of a magnetic field considering both the limits of small and large Zeeman splittings. Particles propagating through a coherent nanoscale device acquire a quantum geometric phase which can have important physical consequences. This geometric phase, known as Berry phase, 1 is acquired through the adiabatic motion of a quantum particle in the system's parameter space and can have strong effects on the transport properties due to selfinterference effects of the quasiparticles when moving in cyclic motion. Its generalization to nonadiabatic motion is known as the Aharonov-Anandan phase.2 A classical example of such geometric phases is the Aharonov-Bohm phase acquired by a particle going around a loop in the presence of a magnetic flux. An important corollary to this phase is the Aharonov-Casher ͑AC͒ phase arising from the propagation of an electron in the presence of spin-orbit coupling. 3This novel effect has attracted strong interest within the spintronic research community which focuses, among other things, on spin-dependent control through electrical means. 4,5 Spintronics has made its way into many niche technological applications-e.g., magnetic memories 6 ͑MRAMs͒-using effects that take place in metals. However, the majority of modern electronic devices are based on semiconductors and more applications will be possible when semiconductor devices can employ the spin degree of freedom as another functional variable in computational processing. The effects of the ac phase on transport through semiconducting ring structures can be tested in two-dimensional ͑2D͒ gas confined to an asymmetric potential well. Such structures enable an all-electrical control of the spins via the Rashba spin-orbit interaction by changing the gate voltage. [7][8][9][10][11] This spin interference in a semiconductor ring ͑see Fig. 1͒ has been proposed as a way to control spin-polarized currents 12,21 and as a spin filter. 13 Signatures of the Aharonov-Casher effect have already been experimentally detected, [14][15][16] and more theoretical 17 and experimental 18 studies have become available recently.Spin interference relies on the spin splitting and, as a result, the devic...

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confidence: 99%

Aharonov-Casher effect in a two-dimensional hole ring with spin-orbit interaction

Kovalev

Borunda²,

Jungwirth³

et al. 2007

Phys. Rev. B

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“…Such a superposition is predicted to produce complex, beating-like magnetoresistance oscillations with nodes developing at particular values of the external Bfield, where the oscillations from the two spin-species have opposite phases [5]. Both h/e and h/2e peaks in the Fourier spectrum of the magnetoresistance oscillations are predicted to be split in the presence of strong SOI [5,15].The interpretation of the split Fourier signal in Ref. [7] has been challenged [16].…”

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Aharonov-Bohm Oscillations in the Presence of Strong Spin-Orbit Interactions

et al. 2007

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We have measured highly visible Aharonov-Bohm (AB) oscillations in a ring structure defined by local anodic oxidation on a p-type GaAs heterostructure with strong spin-orbit interactions. Clear beating patterns observed in the raw data can be interpreted in terms of a spin geometric phase. Besides h/e oscillations, we resolve the contributions from the second harmonic of AB oscillations and also find a beating in these h/2e oscillations. A resistance minimum at B = 0 T, present in all gate configurations, is the signature of destructive interference of the spins propagating along time-reversed paths.Interference phenomena with particles have challenged physicists since the foundation of quantum mechanics. A charged particle traversing a ring-like mesoscopic structure in the presence of an external magnetic flux Φ acquires a quantum mechanical phase. The interference phenomenon based on this phase is known as the Aharonov-Bohm (AB) effect [1], and manifests itself in oscillations of the resistance of the mesoscopic ring with a period of Φ 0 = h/e, where Φ 0 is the flux quantum. The Aharonov-Bohm phase was later recognized as a special case of the geometric phase [2,3] acquired by the orbital wave function of a charged particle encircling a magnetic flux line.The particle's spin can acquire an additional geometric phase in systems with spin-orbit interactions (SOI) [4,5,6]. The investigation of this spin-orbit (SO) induced phase in a solid-state environment is currently the subject of intensive experimental work [7,8,9,10,11,12]. The common point of these experiments is the investigation of electronic transport in ring-like structures defined on two-dimensional (2D) semiconducting systems with strong SOI. Electrons in InAs were investigated in a ring sample with time dependent fluctuations [7], as well as in a ring side coupled to a wire [9]. An experiment on holes in GaAs [8] showed B-periodic oscillations with a relative amplitude ∆R/R < 10 −3 . These observations [7,8] were analyzed with Fourier transforms and interpreted as a manifestation of Berry's phase. Further studies on electrons in a HgTe ring [10] and in an InGaAs ring network [11] were discussed in the framework of the AharonovCasher effect.In systems with strong SOI, an inhomogeneous, momentum dependent intrinsic magnetic field B int , perpendicular to the particle's momentum, is present in the reference frame of the moving carrier [13]. The total magnetic field seen by the carrier is therefore B tot = B ext + B int , where B ext is the external magnetic field perpendicular to the 2D system and B int is the intrinsic magnetic field in the plane of the 2D system present in the moving reference frame (right inset Fig. 1(a)). The particle's spin precesses around B tot and accumulates an additional geometric phase upon cyclic evolution.Effects of the geometric phases are most prominently expressed in the adiabatic limit, when the precession frequency of the spin around the local field B tot is much faster than the orbital frequency of the charged particl...

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“…For example, an attempt to interpret the observed 11 splitting of the AB power spectrum within the diffusion model 10,12 was not successful. In Ref.…”

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confidence: 99%

“…The conductance correlator has been calculated in Ref. 10 for a diffusive ring in the presence of Zeeman coupling and Rashba SOI. It was found that the amplitude of h/e AB peak shows oscillations with varying SOI, similar to those that have been observed for the h/2e peak in Ref.…”

Section: Introductionmentioning

confidence: 99%

Aharonov-Casher oscillations of spin current through a multichannel mesoscopic ring

Shlyapin

Mal’shukov

2010

Phys. Rev. B

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The Aharonov-Casher (AC) oscillations of spin current through a 2D ballistic ring in the presence of Rashba spin-orbit interaction and external magnetic field has been calculated using the semiclassical path integral method. For classically chaotic trajectories the Fokker-Planck equation determining dynamics of the particle spin polarization has been derived. On the basis of this equation an analytic expression for the spin conductance has been obtained taking into account a finite width of the ring arms carrying large number of conducting channels. It was shown that the finite width results in a broadening and damping of spin current AC oscillations. We found that an external magnetic field leads to appearance of new nondiagonal components of the spin conductance, allowing thus by applying a rather weak magnetic field to change a direction of the transmitted spin current polarization.

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Effect of the spin-orbit geometric phase on the spectrum of Aharonov-Bohm oscillations in a semiconductor mesoscopic ring

Cited by 33 publications

References 16 publications

Aharonov-Casher effect in a two-dimensional hole ring with spin-orbit interaction

Aharonov-Casher effect in a two-dimensional hole ring with spin-orbit interaction

Aharonov-Bohm Oscillations in the Presence of Strong Spin-Orbit Interactions

Aharonov-Casher oscillations of spin current through a multichannel mesoscopic ring

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