Optical orientation of nuclei in nitrogen alloys GaAsN at room temperature

Kalevich, V. K.; Afanasiev, M. M.; Shiryaev, A. Yu.; Egorov, A. Yu.

doi:10.1134/s0021364012210060

Cited by 43 publications

(99 citation statements)

References 10 publications

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“…This effect is based on the longitudinal-magnetic-field induced suppression of the electron spin depolarization caused by the hyperfine interaction of a localized electron with the nucleus of the paramagnetic center which localizes this electron. Additionally, the experiment shows that the magnetic-field dependences of PL circular polarization and intensity are shifted with respect to zero field by ∼100 G [10][11][12]. This shift changing its sign with the sign reversal of the pump circular polarization has been attributed [11][12][13] to the Overhauser field B N created by the dynamically polarized nucleus of the paramagnetic center and acting back on the localized electron.…”

Section: Introductionmentioning

confidence: 90%

“…Particularly, the electron spin depolarization in the magnetic field perpendicular to the exciting beam (Hanle effect, the Voigt geometry) is described by a superposition of two Lorentzian contours with widths at half maximum differing by two or three orders: the large spin relaxation time of localized electrons (∼1 ns) determines the width of the narrow contour (∼100 G) whereas the short lifetime of free electrons (∼1 ps) sets the width ∼25 kG of the wide contour [8,9]. Also, it has recently been established [10][11][12][13][14] that the magnetic field directed along the exciting beam (the Faraday geometry) can lead to an increase in the efficiency of spin filter and, as a consequence, to a substantial (up to twice) enhancement of the electron polarization and intensity of the edge photoluminescence (PL) at low and moderate pumping rates. This effect is based on the longitudinal-magnetic-field induced suppression of the electron spin depolarization caused by the hyperfine interaction of a localized electron with the nucleus of the paramagnetic center which localizes this electron.…”

Section: Introductionmentioning

confidence: 99%

“…In Refs. [11][12][13][14] the analysis of the experimental data obtained at room temperature was performed assuming the regime of strong hyperfine coupling of the electron spin with the nuclear spin of the paramagnetic center on which the electron is localized. By definition, in this regime the hyperfine splitting between the levels with angular momenta I +1/2 and I −1/2 (I is the nuclear momentum) exceeds their widths defined by the electron and nuclear reciprocal spin relaxation lifetimes.…”

Section: Introductionmentioning

confidence: 99%

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Spin-dependent recombination in GaAs1–x N x alloys at oblique magnetic field

et al. 2016

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We have studied experimentally and theoretically the optical orientation and spin-dependent Shockley-Read-Hall recombination in a semiconductor in a magnetic field at an arbitrary angle α between the field and circularly polarized exciting beam. The experiments are performed at room temperature in GaAs 1−x N x alloys where deep paramagnetic centers are responsible for the spindependent recombination. The observed magnetic-field dependences of the circular polarization ρ(B) and intensity J(B) of photoluminescence can be approximately described as a superposition of two Lorentzian contours, normal and inverted, with their half-widths differing by an order of magnitude. The normal (narrow) Lorentzian contour is associated with depolarization of the transverse (to the field) component of spin polarization of the localized electrons, whereas the inverted (broad) Lorentzian is due to suppression of the hyperfine interaction of the localized electron with the defect nucleus. The ratio between the height of one Lorentzian and depth of the other is governed by the field tilt angle α. In contrast to the hyperfine interaction of a shallow-donor-bound electron with a large number of nuclei of the crystal lattice, in the optical orientation of the electron-nuclear system under study no additional narrow peak appears in the oblique field. This result demonstrates that in the GaAsN alloys the hyperfine interaction of the localized electron with the single nucleus of the paramagnetic center remains strong even at room temperature. For a theoretical description of the experiment, we have extended the theory of spin-dependent recombination via deep paramagnetic centers with the nuclear angular momentum I = 1/2 developed previously for the particular case of the longitudinal field. The calculated curves ρ(B), J(B) agree with the approximate description of the experimental dependences as a sum of two Lorentzians, and an additional narrow shifted peak does not appear in the computation as well.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spin-dependent recombination in GaAs1–x N x alloys at oblique magnetic field

et al. 2016

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“…As demonstrated by Kalevich and Korenev, these corrections introduce off-diagonal elements into the g factor tensor, which therefore has three independent components, i.e., g xx = g yy , g zz , and g xy = g yx = 0. 13 This yields an in-plane anisotropy of the g factor which is given by 10,13,22 …”

Section: Origin Of G * Anisotropymentioning

confidence: 99%

“…In (001) quantum wells, anisotropy of s requires, in addition to the bulk inversion asymmetry term (BIA), another spin-orbit term of the same form as the structural inversion asymmetry (SIA) term, 12 whereas for an anisotropic g * an asymmetric conduction electron wave function is needed. 13 Therefore, simultaneous measurement of the anisotropy of s and g * can be used as a powerful tool to directly reveal the microscopic effects on the structure. In Refs.…”

Section: Introductionmentioning

confidence: 99%

Effect of symmetry reduction on the spin dynamics of (001)-oriented GaAs quantum wells

et al. 2013

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Spin quantum beat spectroscopy is employed to investigate the in-plane anisotropy of the spin dynamics in (001) GaAs/AlGaAs quantum wells induced by an external electric field. This technique allows the anisotropy of the spin relaxation rate s and the electron Landé g factor g * to be measured simultaneously. The measurements are compared to similar data from (001) GaAs/AlGaAs quantum wells with applied shear strain and asymmetric barrier growth. All of these operations act to reduce the symmetry compared to that of a symmetric (001) quantum well in an identical manner (D 2d → C 2v ). However, by looking at the anisotropy of both s and g * simultaneously we show that the microscopic actions of these symmetry breaking operations are very different. The experiments attest that although symmetry arguments are a very useful tool to identify the allowed spin dependent properties of a material system, only a microscopic approach reveals if allowed anisotropies will manifest.

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A Systematic Study of Spin‐Dependent Recombination in GaAs_1−xN_x as a Function of Nitrogen Content

Ulibarri¹,

Kothari²,

Garcia³

et al. 2022

Physica Status Solidi (b)

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A systematic study of spin‐dependent recombination (SDR) under steady‐state optical pumping conditions as a function of nitrogen content, x, in dilute nitride alloys of the form GaAs1−xNx is reported. Use of high‐excitation power densities up to 107 W cm−2 allows measurement of the full SDR versus power curves, even at relatively high nitrogen contents of x = 0.039. Alloy contents for 0.022≤x≤0.039 are determined within δx = ±0.005 by fitting the photoluminescence (PL) spectra using a Roosbroeck–Shockley relation, and values consistent with those obtained by studying the intensity of the GaN‐like LO2 Raman mode are found. PL intensity increases by a factor known as the SDR ratio when switching from linearly to circularly polarized pump excitation. This factor reaches 5 for x = 0.022 and decreases with increasing x, falling to 1.5 for x = 0.039. Moreover, the excitation power required for maximum SDR increases with increasing x, varying from 0.6 mW for x = 0.022 to 15 mW for x = 0.039. These observations indicate an increase in the density of electronically active defects with increasing nitrogen content, both responsible for the SDR and other, standard Shockley–Read–Hall centers. The result demonstrates the importance of including nonspin‐dependent recombination channels in a complete model of SDR.

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Optical orientation of nuclei in nitrogen alloys GaAsN at room temperature

Cited by 43 publications

References 10 publications

Spin-dependent recombination in GaAs1–x N x alloys at oblique magnetic field

Spin-dependent recombination in GaAs1–x N x alloys at oblique magnetic field

Effect of symmetry reduction on the spin dynamics of (001)-oriented GaAs quantum wells

A Systematic Study of Spin‐Dependent Recombination in GaAs_1−xN_x as a Function of Nitrogen Content

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Optical orientation of nuclei in nitrogen alloys GaAsN at room temperature

Cited by 43 publications

References 10 publications

Spin-dependent recombination in GaAs1–x N x alloys at oblique magnetic field

Spin-dependent recombination in GaAs1–x N x alloys at oblique magnetic field

Effect of symmetry reduction on the spin dynamics of (001)-oriented GaAs quantum wells

A Systematic Study of Spin‐Dependent Recombination in GaAs1−xNx as a Function of Nitrogen Content

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A Systematic Study of Spin‐Dependent Recombination in GaAs_1−xN_x as a Function of Nitrogen Content