Persistent spin helix manipulation by optical doping of a CdTe quantum well

Passmann, F.; Anghel, S.; Tischler, Tobias; Poshakinskiy, A. V.; Tarasenko, S. A.; Karczewski, G.; Wójtowicz, T.; Bristow, Alan D.; Betz, M.

doi:10.1103/physrevb.97.201413

Cited by 21 publications

(9 citation statements)

References 39 publications

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“…We emphasize that this peculiar spin wave mode emerges as an intrinsic property of the bulk phase, thus does not rely on fine tuning of Rashba and Dresselahus parameters which was a strong requirement to realize the PSH in semiconductor quantum wells explored in last years. [34][35][36][37][38][39] In particular, we have shown that the crystal symmetry (space group P 2 1 am) and the point group of the Γ point (C 2v ) around which the spin-splitting occurs, perfectly match the requirements for the PSH design, as it allows for coexisting Rashba and Dresselhaus couplings. Our DFT calculations reveal that these SOC parameters compensate well and the spin texture can be considered quasi-independent from the momentum.…”

Section: K • P Analysis Of Valence-band Spin Polarizationsmentioning

confidence: 71%

Persistent spin helix in Rashba-Dresselhaus ferroelectric CsBiNb2O7

Autieri

Barone

Sławińska

et al. 2019

Phys. Rev. Materials

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Ferroelectric Rashba semiconductors (FERSC) are a novel class of multifunctional materials showing a giant Rashba spin splitting which can be reversed by switching the electric polarization. Although they are excellent candidates as channels in spin field effect transistors, the experimental research has been limited so far to semiconducting GeTe, in which ferroelectric switching is often prevented by heavy doping and/or large leakage currents. Here, we report that CsBiNb2O7, a layered perovskite of Dion-Jacobson type, is a robust ferroelectric with sufficiently strong spin-orbit coupling and spin texture reversible by electric field. Moreover, we reveal that its topmost valence band's spin texture is quasi-independent from the momentum, as a result of the low symmetry of its ferroelectric phase. The peculiar spin polarization pattern in the momentum space may yield the so-called "persistent spin helix", a specific spin-wave mode which protects the spin from decoherence in diffusive transport regime, potentially ensuring a very long spin lifetime in this material.

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Section: K • P Analysis Of Valence-band Spin Polarizationsmentioning

confidence: 71%

Persistent spin helix in Rashba-Dresselhaus ferroelectric CsBiNb2O7

Autieri

Barone

Sławińska

et al. 2019

Phys. Rev. Materials

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“…The dotted curve represents γ s calculated with the parameters of CdTe (E b = 10 meV, a B = 5.2 nm, δ e = 2π × 29 MHz) with n d = 10 14 cm −3 and γ D = 12µeV Å3 in the range of published values [35][36][37]. For this doping level one can distinguish the three different spin relaxation regimes.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

Spatiotemporal electronic spin fluctuations in random nuclear fields in n-CdTe

Cronenberger,

Abbas,

Scalbert

et al. 2019

Preprint

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We report on the dynamics of electron spins in n-doped CdTe layers that differs significantly from the expected response derived from the studies dedicated to electron spin relaxation in n-GaAs. At zero magnetic field, the electron spin noise spectra exhibit a two-peak structure -a zero-frequency line and a satellite -that we attribute to the electron spin precession in a frozen random nuclear spin distribution. This implies a surprisingly long electron spin correlation time whatever the doping level, even above the Mott transition. Using spatiotemporal spin noise spectroscopy, we demonstrate that the observation of a satellite in the spin noise spectra and a fast spin diffusion are mutually exclusive. This is consistent with a shortening of the electron spin correlation time due to hopping between donors. We interpret our data via a model assuming that the low temperature spin relaxation is due to hopping between donors in presence of hyperfine and anisotropic exchange interactions. Most of our results can be interpreted in this framework. First, a transition from inhomogeneous to homogeneous broadening of the spin noise peaks and the disappearance of the satellite are observed when the hopping rate becomes larger than the Larmor period induced by the local nuclear fields. In the regime of homogeneous broadening the ratio between the spin diffusion constant and the spin relaxation rate has a value in good agreement with the Dresselhaus constant. In the regime of inhomogeneous broadening, most of the samples exhibit a broadening consistent with the distribution of local nuclear fields. We obtain a new estimate of the hyperfine constants in CdTe and a value of 0.10 Tesla for the maximum nuclear field. Finally, our study also reveals a puzzle as our samples behave as if the active donor concentration was reduced by several orders of magnitudes with respect to the nominal values.

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“…This twofold material choice is of great scientific interest as it allows for a comparison of the PSH characteristics in materials with different SO interaction strength. In addition, PSH physics in II-VI compounds has not been studied extensively [7,48].…”

Section: Sample Characteristics Of Cdte and Gaas Quantum Wellsmentioning

confidence: 99%

“…Thus, the value of l so,y observed at a specific delay time depends on the initial spot size w 0 and the diffusion coefficient D s [48]. 2together with other sample specific parameters.…”

mentioning

confidence: 99%

Dynamical formation and active control of persistent spin helices in III-V and II-VI quantum wells

Passmann

Anghel

Ruppert

et al. 2019

Semicond. Sci. Technol.

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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 spinorbit 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.

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Persistent spin helix manipulation by optical doping of a CdTe quantum well

Cited by 21 publications

References 39 publications

Persistent spin helix in Rashba-Dresselhaus ferroelectric CsBiNb2O7

Persistent spin helix in Rashba-Dresselhaus ferroelectric CsBiNb2O7

Spatiotemporal electronic spin fluctuations in random nuclear fields in n-CdTe

Dynamical formation and active control of persistent spin helices in III-V and II-VI quantum wells

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