Mesoscopic rings with spin-orbit interactions

An exact solution for single electron states on mezoscopic rings with the Rashba coupling and in the presence of external magnetic and electric fields is derived by means of a unitary transformation. The transformation maps the model to a bare ring, which gives the possibility of a very simple formulation of single or many electron problems. As an example some exact results for spin and energy levels are presented.

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“…If written by components, it is evident that this reproduces know results from 31,29,32,33,34 . The corresponding eigenenergies are then…”

Section: Eigenstates Of Free Electrons: Energy and Spin Propertiessupporting

confidence: 62%

Exact unitary transformation for Rashba Rings in magnetic and electric fields

Kregar

Ramšak

2016

Int. J. Mod. Phys. B

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“…The elements d 00 , d ij are T -even and P -odd, while the coefficients d 0i are T -odd and P -even. The T-even character of d 00 , d ij will allow to obtain persistent spin current but no charge current [25,29,31] in the next sections.…”

Section: Induction Of Geometrical Phases and Persistent Spin Currentsmentioning

confidence: 99%

“…It was verified that the nonrelativistic limit of the mass term, H μν σ μν , leads to the Rashba spin-orbit interaction, that appears as a consequence of an inversion asymmetry potential in a semiconductor interface, in the presence of an electric field [31]. In this case, the tensor component H 0i corresponds to the Rashba coupling constant (α R ): α R = H 0i /m, so that H 0i plays the role of the electric field, E. The Rashba term has appeared also in the context of the Dirac equation modified by a CPT-even nonminimal coupling [42] and a CPT-odd nonminimal coupling [43].…”

Section: Introductionmentioning

confidence: 98%

Generation of geometrical phases and persistent spin currents in 1-dimensional rings by Lorentz-violating terms

et al. 2015

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We have demonstrated that Lorentz-violating terms stemming from the fermion sector of the SME are able to generate geometrical phases on the wave function of electrons confined in 1-dimensional rings, as well as persistent spin currents, in the total absence of electromagnetic fields. We have explicitly evaluated the eigenenergies and eigenspinors of the electrons modified by the Lorentz-violating terms, using them to calculate the dynamic and the Aharonov-Anandan phases in the sequel. The total phase presents a pattern very similar to the Aharonov-Casher phase accumulated by electrons in rings under the action of the Rashba interaction. Finally, the persistent spin current were carried out and used to impose upper bounds on the Lorentz-violating parameters.

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“…[11,12] in the basis {p, σ } where σ = ↑, ↓ are spin orientations with respect to the z-axis. It is derived by a standard discretization of the Hamiltonian presented by Meijer et al [20] (see also a detailed recent derivation [21]). …”

Section: Formalismmentioning

confidence: 99%

Mesoscopic Fano effect in a spin splitter with a side-coupled quantum dot

2012

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We investigate the interplay between the spin interference and the Fano effect in a three-lead mesoscopic ring with a side-coupled quantum dot (QD). A uniform Rashba spin-orbit coupling and a perpendicular magnetic field are tuned such that the ring operates as a spin splitter in the absence of the QD: one lead is used to inject unpolarized electrons and the remaining (output) leads collect almost polarized spin currents. By applying a gate potential to the quantum dot a pair of spin-split levels sweeps the bias window and leads to Fano interference. The steady-state spin and charge currents in the leads are calculated for a finite bias applied across the ring via the non-equilibrium Green's function formalism. When the QD levels participate to transport we find that the spin currents exhibit peaks and dips whereas the charge currents present Fano lineshapes. The location of the side-coupled quantum dot and the spin splitting of its levels also affect the interference and the output currents. The opposite response of output currents to the variation of the gate potential allows one to use this system as a single parameter current switch. We also analyze the dependence of the splitter efficiency on the spin splitting on the QD.

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Mesoscopic rings with spin-orbit interactions

Cited by 49 publications

References 39 publications

Exact unitary transformation for Rashba Rings in magnetic and electric fields

Exact unitary transformation for Rashba Rings in magnetic and electric fields

Generation of geometrical phases and persistent spin currents in 1-dimensional rings by Lorentz-violating terms

Mesoscopic Fano effect in a spin splitter with a side-coupled quantum dot

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