7 results on '"SPIN polarization"'
Search Results
2. Dynamical formation and active control of persistent spin helices in III-V and II-VI quantum wells.
- Author
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Passmann, F, Anghel, S, Ruppert, C, Bristow, A D, Poshakinskiy, A V, Tarasenko, S A, and Betz, M
- Subjects
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MONTE Carlo method , *SPIN-orbit interactions , *SPIN polarization , *CARRIER density , *ELECTRIC fields , *NUCLEAR spin , *QUANTUM wells - Abstract
This review article summarizes recent developments related to the dynamical formation of persistent spin helices in GaAs- and CdTe-based heterostructures. We start with fundamental aspects of spin-orbit interaction in quantum wells, in particular the Dresselhaus and Rashba terms and their relation to the bulk and structural inversion asymmetries, respectively. In the regime of balanced interactions, their combined impact gives rise to the formation of the persistent spin helix, i.e., a regime where a unidirectional spin grating with enhanced coherence time is established. The experimental scheme relies on ultrafast Kerr microscopy and permits to excite the spin polarization and detect it with a simultaneous spatial and temporal resolution of micrometers and picoseconds, respectively. For a microscopic understanding and a description of the results, kinetic theory of spatio-temporal spin dynamics of two-dimensional electrons is presented. In addition, Monte Carlo simulations of the spin distribution function are performed. Based on these concepts we discuss three areas with recent advances in the field of spin helices. (i) Anisotropic spin transport and spin helix dynamics in a modulation-doped GaAs quantum well is analyzed. It is observed that application of an out-of-plane electric field changes spin-orbit interaction through the Rashba component and the cubic Dresselhaus term. Remarkably, a weak in-plane electric field substantially increases spin diffusion and also affects the spin helix wavelength. (ii) In-plane magnetic fields applied in two perpendicular orientations allow for the extraction of the individual spin–orbit coupling parameters. (iii) Finally, we explore the influence of optical doping on the spin helix in a CdTe quantum well. Most importantly, a non-uniform spatio-temporal precession pattern is observed. The kinetic theory of spin diffusion allows us to model this finding by incorporating a dependence on the photo-carrier density into the Rashba and the Dresselhaus parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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3. Spin depolarization under low electric fields at low temperatures in undoped InGaAs/AlGaAs multiple quantum well.
- Author
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Laipan Zhu, Yu Liu, Chongyun Jiang, Jinling Yu, Hansong Gao, Hui Ma, Xudong Qin, Yuan Li, Qing Wu, and Yonghai Chen
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QUANTUM wells , *INDIUM gallium arsenide , *LOW temperatures , *SPIN polarization , *ELECTRIC fields , *PHOTOINDUCED electron transfer - Abstract
The spin polarization under low electric fields ( =300 V/cm) at low temperatures has been studied in undoped InGaAs/AlGaAs multiple quantum well. The spin polarization was created by optical spin orientation using circularly polarized light and the inverse spin-Hall effect was employed to measure the spin polarization current. We observed an obvious spin depolarization especially at lower temperatures (80-120K). We ascribed the spin depolarization of the photoinduced electrons to the heating effect from the low electric fields (the low field regime 50-300V/cm). This spin depolarization due to the heating effect is sensitive to temperature and electric field, suggesting a wide range of potential applications and devices. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
4. Controllable spin transport in dual-gated silicene.
- Author
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Yu Wang and Yiyi Lou
- Subjects
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SILICON , *RESONANT tunneling , *POLARIZED beams (Nuclear physics) , *SPIN polarization , *ELECTRIC fields , *QUANTUM wells - Abstract
Based on the dual-gated silicene, we have evaluated theoretically the spin-dependent transport in lateral resonant tunneling structure. By aligning the completely valley-polarized beam with spin-resolved well state in concerned structure, large spin polarization can be expected owing to spin-dependent resonant tunneling mechanism. Under the gate electric field modulation, the forming quantum well state can be externally manipulated, triggering further the emergence of externally-controllable spin polarization. Importantly, integrating the considered structure with a proper valley-filter, which might be constructed from valley-contrasting physics as that in graphene valleytronics, completely-polarized spin beam can also be attained without the assistance of ferromagnetic component, providing thus some profitable strategies to develop nonmagnetic spintronic devices residing on silicene. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
5. Current-Induced Spin Photocurrent in GaAs at Room Temperature.
- Author
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Zhang, Yang, Liu, Yu, Xue, Xiao-Lan, Zeng, Xiao-Lin, Wu, Jing, Shi, Li-Wei, and Chen, Yong-Hai
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AUDITING standards , *SPIN polarization , *GALLIUM arsenide , *ELECTRIC fields , *QUANTUM wells , *TEMPERATURE - Abstract
Circularly polarized photocurrent, observed in p-doped bulk GaAs, varies nonlinearly with the applied bias voltage at room temperature. It has been explored that this phenomenon arises from the current-induced spin polarization in GaAs. In addition, we found that the current-induced spin polarization direction of p-doped bulk GaAs grown in the (001) direction lies in the sample plane and is perpendicular to the applied electric field, which is the same as that in GaAs quantum well. This research indicates that circularly polarized photocurrent is a new optical approach to investigate the current-induced spin polarization at room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
6. RESONANT SPIN POLARIZATION IN A TWO-DIMENSIONAL HOLE GAS.
- Author
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MA, TIANXING
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POLARIZATION (Electricity) , *RESONANCE , *ELECTRON gas , *HOLES (Electron deficiencies) , *ELECTRIC fields , *MAGNETIC fields , *QUANTUM wells , *SPINTRONICS - Abstract
Within the Luttinger Hamiltonian, electric-field-induced resonant spin polarization of a two-dimensional hole gas in a perpendicular magnetic field was studied. The spin polarization arising from splitting between the light and the heavy hole bands shows a resonant peak at a certain magnetic field. Especially, the competition between the Luttinger term and the structural inversion asymmetry leads to a rich resonant peaks structure, and the required magnetic field for the resonance may be effectively reduced by enlarging the effective width of the quantum well. Furthermore, the Zeeman splitting tends to move the resonant spin polarization to a relative high magnetic field and destroy these rich resonant spin phenomena. Finally, both the height and the weight of the resonant peak increase as the temperature decreases. It is believed that such resonant spin phenomena may be verified in the sample of a two-dimensional hole gas, and it may provide an efficient way to control spin polarization by an external electric field. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
7. Temperature dependent electric field control of the electron spin relaxation in (111)A GaAs quantum wells
- Author
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Gang Wang, W. X. Wang, Andrea Balocchi, Pierre Renucci, C. Zhu, Delphine Lagarde, Thierry Amand, Xavier Marie, Z. W. Shi, Baoli Liu, Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences [Beijing] (CAS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Magnetic ordering ,Electric fields ,Physics and Astronomy (miscellaneous) ,Stark effect ,Multiple quantum ,Electronic bandstructure ,Substrate (electronics) ,Zero field splitting ,01 natural sciences ,010305 fluids & plasmas ,Gallium arsenide ,chemistry.chemical_compound ,Electric field ,0103 physical sciences ,010306 general physics ,Quantum well ,Physics ,[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics] ,Condensed matter physics ,Spin polarization ,Photoluminescence spectroscopy ,Condensed Matter::Other ,Relaxation (NMR) ,Leptons ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electronic transport ,Quantum wells ,chemistry ,Semiconductors ,Time-resolved photoluminescence - Abstract
International audience; We demonstrate the electrical control of the electron spin relaxation in GaAs/AlGaAs multiple quantum wells grown on (111)A substrate. By embedding the wells in a NIP structure, the application of an external bias yields a large increase of the electron spin relaxation time due to the compensation of the Dresselhaus spin-splitting by the Rashba one. Depending on the direction of the applied electric field, the electron spin relaxation can be slowed-down or sped-up. It can be tuned by a factor 50 at 75 K and still by a factor 2 at 250 K.
- Published
- 2013
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