Anisotropic spin dephasing of impurity-bound electron spins in ZnO

Lee, Jieun; Venugopal, Aneesh; Sih, Vanessa

doi:10.1063/1.4905278

Cited by 6 publications

(9 citation statements)

References 23 publications

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“…Furthermore, in n-type bulk ZnO, it has been reported that for donor-bound electrons the spin relaxation is strongly anisotropic. 7 It was claimed that the defects present in the sample due to impurities, induce bound exciton in the vicinity of donor states which further contribute to the spin signal. This contribution to the bound electron spins at donor sites is more predominant at low temperatures and leads to relaxation anisotropy.…”

Section: Resultsmentioning

confidence: 99%

Large anisotropic spin relaxation time of exciton bound to donor states in triple quantum wells

Ullah

Gusev

Bakarov

et al. 2017

Journal of Applied Physics

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We have studied the spin dynamics of a dense two-dimensional electron gas confined in a GaAs/AlGaAs triple quantum well by using time-resolved Kerr rotation and resonant spin amplification. Strong anisotropy of the spin relaxation time up to a factor of 10 was found between the electron spins oriented in-plane and out-of-plane when the excitation energy is tuned to an exciton bound to neutral donor transition. We model this anisotropy using an internal magnetic field and the inhomogeneity of the electron g-factor. The data analysis allows us to determine the direction and magnitude of this internal field in the range of a few mT for our studied structure, which decreases with the sample temperature and optical power. The dependence of the anisotropic spin relaxation was directly measured as a function of several experimental parameters: excitation wavelength, sample temperature, pump-probe time delay, and pump power. a) Corresponding author. Electronic address: felixggh@if.usp.br arXiv:1703.07156v2 [cond-mat.mes-hall]

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Section: Resultsmentioning

confidence: 99%

Large anisotropic spin relaxation time of exciton bound to donor states in triple quantum wells

Ullah

Gusev

Bakarov

et al. 2017

Journal of Applied Physics

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“…Detailed study of spin relaxation anisotropy as a function of experimental parameters (namely, sample temperature, pump-probe delay and optical power) can be found in Ref. [24].The observed long T * 2 in the out-of-plane direction for both sample A and B stipulates that the scattering-induced DP mechanism is weak in the studied structures [12]. However, combined with the inhomogeneous spread of g-factor it leads to a strong T * 2 reduction.…”

Section: Spin Dynamics In Sample Bmentioning

confidence: 99%

Tailoring multilayer quantum wells for spin devices

et al. 2018

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The electron spin dynamics in multilayer GaAs/AlGaAs quantum wells, containing high-mobility dense two-dimensional electron gases, have been studied using time-resolved Kerr rotation and resonant spin amplification techniques. The electron spin dynamics was regulated through the wave function engineering and quantum confinement in multilayer quantum wells. We observed the spin coherence with a remarkably long dephasing time T * 2 > 13 ns for the structure doped beyond metal-insulator transition. Dyakonov-Perel spin relaxation mechanism, as well as the inhomogeneity of electron g-factor, was suggested as the major limiting factors for the spin coherence time. In the metallic regime, we found that the electron-electron collisions become dominant over microscopic scattering on the electron spin relaxation with the Dyakonov-Perel mechanism. Furthermore, the data analysis indicated that in our structure, due to the spin relaxation anisotropy, Dyakonov-Perel spin relaxation mechanism is efficient for the spins oriented in-plane and suppressed along the quantum well growth direction resulting in the enhancement of T * 2 . Our findings, namely, long-lived spin coherence persisting up to about room temperature, spin polarization decay time with and without a magnetic field, the spin-orbit field, single electron relaxation time, transport scattering time, and the electron-electron Coulomb scattering time highlight the attractiveness of n-doped multilayer systems for spin devices.

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“…In bulk semiconductors with wurtzite or zinc-blende crystalline structures, the antisymmetric part of the anisotropic exchange of the localized electrons is dominated by Dzyaloshinskii-Moriya 15 interaction (DMI) 63,64 which is the first-order perturbation in SOI of Rashba 65 showing anisotropic dephasing in bulk GaN and impurity-bound electrons in n-doped ZnO. 54,55 There have been theoretical and experimental demonstrations of magnetic orderings in semiconductors. 52,56,60,[67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] In order to be more specific, we propose a system of interstitial impurities and oxygen vacancies in a metal-oxide.…”

Section: B Physical Feasibility Of the S M -Mechanismmentioning

confidence: 99%

Cloaking the magnons

Elyasi¹,

Bhatia²,

Qiu³

et al. 2016

Phys. Rev. B

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We propose two approaches to cloak the spin waves (magnons) by investigating magnetization dynamics. One approach is based on a spatially inhomogeneous anisotropic magnetic moment tensor. The other mechanism is using a spatially inhomogeneous anisotropic gyromagnetic factor tensor and an inhomogeneous external magnetic field. For both approaches, the damping tensor is also inhomogeneous and anisotropic. The magnetic characteristic functions of the magnetic materials have been theoretically derived for both mechanisms. A non-magnetic core, which prevents magnons from entering and consequently distorts the spin wave propagation, can be cloaked by a structured magnetic shell to redirect the spin wave around the core using the above design mechanisms. We discuss the feasibility of the proposed mechanisms in an ensemble of quantum dot molecules and magnetic semiconductors. The proposed approaches shed light on transformation magnonics, and can be utilized for future spin-wave lenses, concentrators, low back-scattering waveguides, and ultimately quantum computing.Comment: Accepted for publication in Phys. Rev.

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Anisotropic spin dephasing of impurity-bound electron spins in ZnO

Cited by 6 publications

References 23 publications

Large anisotropic spin relaxation time of exciton bound to donor states in triple quantum wells

Large anisotropic spin relaxation time of exciton bound to donor states in triple quantum wells

Tailoring multilayer quantum wells for spin devices

Cloaking the magnons

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