Spin transmission control in helical magnetic fields

Saarikoski, Henri; Dollinger, Tobias; Richter, Klaus

doi:10.1103/physrevb.86.165407

Cited by 10 publications

(28 citation statements)

References 19 publications

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“…6-c and d, it opens the possibility to profit from situations where quantum interference becomes relevant. [64,66] With increasing system's size, molecular electronics suffers a paradigm shift on its dominant transport mechanism, from "coherent tunneling" to "incoherent hopping". Within this context, the present work should result specially helpful in providing a computational bridge between these limiting situations, while maintaining a general, transparent, and efficient approach to quantum transport.…”

Section: Discussionmentioning

confidence: 99%

Generalized multi-terminal decoherent transport: recursive algorithms and applications to SASER and giant magnetoresistance

Cattena

Fernández-Alcázar

Bustos-Marún

et al. 2014

J. Phys.: Condens. Matter

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Decoherent transport in mesoscopic and nanoscopic systems can be formulated in terms of the D'Amato-Pastawski (DP) model. This generalizes the Landauer-Büttiker picture by considering a distribution of local decoherent processes. However, its generalization for multi-terminal setups is lacking. We first review the original two-terminal DP model for decoherent transport. Then, we extend it to a matrix formulation capable of dealing with multi-terminal problems. We also introduce recursive algorithms to evaluate the Green's functions for general banded Hamiltonians as well as local density of states, effective conductances and voltage profiles. We finally illustrate the method by analyzing two problems of current relevance. 1) Assessing the role of decoherence in a model for phonon lasers (SASER). 2) Obtaining the classical limit of Giant Magnetoresistance from a spin-dependent Hamiltonian. The presented methods should pave the way for computationally demanding calculations of transport through nanodevices, bridging the gap between fully coherent quantum schemes and semiclassical ones.

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Section: Discussionmentioning

confidence: 99%

Generalized multi-terminal decoherent transport: recursive algorithms and applications to SASER and giant magnetoresistance

Cattena

Fernández-Alcázar

Bustos-Marún

et al. 2014

J. Phys.: Condens. Matter

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“…The second important ingredient to the effective spinorbit coupling in quantum wells is known as the Rashba term and is due to structure-inversion asymmetry, i.e. it occurs for confining potentials failing to be invariant under spatial inversion along the growth direction (Bychkov and Rashba, 1984;Rashba, 1960). This contribution is described by the expression…”

Section: Introductionmentioning

confidence: 99%

“…where the Rashba coefficient α is essentially proportional to the potential gradient across the quantum well and can therefore be varied experimentally. This contribution to spin-orbit interaction is the essential ingredience to the proposal for a spin field -effect transistor due to Datta and Das (1990) (Bychkov and Rashba, 1984;Rashba, 1960), it is nowadays discussed and studied in a much wider variety of structures lacking inversion symmetry; for a recent overview see Manchon et al (2015). A further source of spin-orbit coupling in two-dimensional structures are assymetric interfaces (Fabian et al, 2007); such contributions will not be considered in the following.…”

Section: Introductionmentioning

confidence: 99%

Colloquium: Persistent spin textures in semiconductor nanostructures

2017

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Device concepts in semiconductor spintronics make long spin lifetimes desirable, and the requirements put on spin control by schemes of quantum information processing are even more demanding. Unfortunately, due to spin-orbit coupling electron spins in semiconductors are generically subject to rather fast decoherence. In two-dimensional quantum wells made of zinc-blende semiconductors, however, the spin-orbit interaction can be engineered in such a way that persistent spin structures with extraordinarily long spin lifetimes arise even in the presence of disorder and imperfections. We review experimental and theoretical developments on this subject both for n-doped and p-doped structures, and we discuss possible device applications.

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“…The calculations of the conductance as a function of the Fermi energy reveals additional conductance dips, which cannot be understood in terms of the ordinary Landau-Zener theory. This effect, not reported in the previous studies, 15,19 is explained as resulting from the resonant inter-subband transition between the spatially modulated spin-dependent subbands. We consider a two-dimensional waveguide (nanowire) in the x − y plane made of (Cd,Mn)Te in the presence of the magnetic field B(r), which is the superposition of the homogeneous magnetic field applied along the z-axis B ext = (0, 0, −B ext ) and the helical magnetic field B h (r) taken on in the form 19…”

Section: Pacs Numbers: XXXmentioning

confidence: 44%

Resonant Landau–Zener transitions in a helical magnetic field

Wójcik

Adamowski

Wołoszyn

et al. 2015

Semicond. Sci. Technol.

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The spin-dependent electron transport has been studied in magnetic semiconductor waveguides (nanowires) in the helical magnetic field. We have shown that -apart from the known conductance dip located at the magnetic field equal to the helical-field amplitude B h -the additional conductance dips (with zero conductance) appear at magnetic field different from B h . This effect occuring in the non-adiabatic regime is explained as resulting from the resonant Landau-Zener transitions between the spin-splitted subbands. PACS numbers: xxxThe experimental realization of an effective spintransistor remains a challenge facing spintronics since the pioneering concept proposed by Datta and Das. 1 According to the original idea the operation of the spin transistor is based on the gate-controlled spin-orbit interaction (SOI) of Rashba form. 2 The current of spin polarized electrons is injected from the ferromagnetic source into the conduction channel formed in a two-dimensional electron gas (2DEG) and is ballistically transported to the ferromagnetic drain. The state of the transistor depends on the electron spin orientation modulated via the Rashba SOI by the voltage applied to the gate attached close to the channel. The operation of spin transistor has been studied in many theoretical papers. 3-7 However, the experiments 8,9 indicate that the signals obtained in the up-to-date realized spin transistors based on the SOI are rather low, which results from the low efficiency of the spin injection from the ferromagnet into the semiconductor 10 and the spin relaxation. The SOI causes that the scattering processes affect the spin states of electrons, e.g., by the Elliott-Yafet or Dyakonov-Perel mechanism. 11 Although the spin relaxation is proposed to be suppressed by equating the Rashba and Dresselhaus term, 12,13 the concept of the non-ballistic spin transistor proposed by Schliemann et al. in Ref. 12 is still waiting for the experimental realizations.An alternative spin-transistor design, with the spin relaxation length as long as 50 µm, has been recently described byŽutić and Lee 14 and experimentally demonstrated by Betthausen et al. in Ref. 15. In this approach, the spin control is realized by combining the homogeneous and helical magnetic fields. The latter is generated by ferromagnetic stripes located above the conduction channel. The spin state of electrons flowing through the channel is protected against a possible decay by keeping the transport in the adiabatic regime. 16 The transistor action is driven by the diabatic Landau-Zener transitions 17,18 induced by the appropriate tuning of the homogeneous magnetic field. For these suitably chosen conditions the backscattering of spin polarized electrons appears, which gives raise to the large increase of the resistance, i.e., the transistor goes over into the 'off' state. In contrast to the SOI-based spin transistor, the proposed design is robust against the scattering processes. 19Motivated by the experiment, 15 we have performed the computer simulations of the spin-depend...

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Spin transmission control in helical magnetic fields

Cited by 10 publications

References 19 publications

Generalized multi-terminal decoherent transport: recursive algorithms and applications to SASER and giant magnetoresistance

Generalized multi-terminal decoherent transport: recursive algorithms and applications to SASER and giant magnetoresistance

Colloquium: Persistent spin textures in semiconductor nanostructures

Resonant Landau–Zener transitions in a helical magnetic field

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