Room temperature spin relaxation in GaAs/AlGaAs multiple quantum wells

Britton, R.S.; Grevatt, T.; Malinowski, A.; Harley, R. T.; Perozzo, P.; Cameron, A. R.; Miller, A.

doi:10.1063/1.122403

Cited by 85 publications

(66 citation statements)

References 14 publications

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“…The first and second terms in equation (3) are associated with the optically induced linear and circular birefringence and are known as the SOKE and the specular inverse Faraday effect (SIFE), respectively. Our rotation measurements do not fully characterize the cubic susceptibility tensor, only the combination of components given in equations (4) and (5). From figures 4, 6 and 8 we might conclude that the SIFE dominates the zero-delay peak in GaAs [7], the SOKE is dominant in Al, while the more complicated dependence in Ni is the result of competition between the SIFE and the SOKE.…”

Section: Discussionmentioning

confidence: 90%

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Investigation of transient linear and circular birefringence in metallic thin films

Wilks¹,

Hughes²,

Hicken³

2003

J. Phys.: Condens. Matter

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Optical pump-probe measurements have been performed on three materials with pump pulses of 120 fs duration and variable helicity. The samples were probed in a reflection geometry. We compare the transient intensity and rotation signals induced in intrinsic GaAs wafers and sputtered polycrystalline Ni and Al thin films. An initial peak is observed in the transient rotation signal. The dependence of the peak height on the polarization of the pump is found to be qualitatively different for the three materials, indicating different amounts of linear and circular birefringence in each case. For ferromagnetic Ni the peak is superimposed on a longer-lived ultra-fast demagnetization signal. For GaAs and Al we also observe a tail in the rotation signal that decays on time-scales of several picoseconds. In the case of GaAs, we attribute this to the relaxation of a spin polarization that is induced by the pump beam within the thermal electron population. In the case of Al, the dependence of the amplitude of the tail on the pump beam's polarization is characteristic of linear birefringence. We suggest that this signal is associated with an ultra-fast excitation of the lattice rather than with optical orientation of spin.

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Section: Discussionmentioning

confidence: 90%

“…Spin relaxation effects in semiconductors and quantum well structures have been studied intensively [5]. The coherent control of spin orientation has been demonstrated in experiments performed at low temperatures and in high magnetic fields,and using the optical Stark effect [6].…”

Section: Introductionmentioning

confidence: 99%

Investigation of transient linear and circular birefringence in metallic thin films

Wilks¹,

Hughes²,

Hicken³

2003

J. Phys.: Condens. Matter

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“…In contrast to GaAsbased systems, relatively little attention has been paid to InAs, even although it may be important in future spintronics applications. We previously measured spin lifetimes in narrow-gap semiconductors ͑NGSs͒, Hg 1Ϫx Cd x Te and InSb, at wavelengths between 4 and 10 m over the temperature range of 4 to 300 K. 4 We have now extended those measurements to include bulk epilayers of InAs as a function of doping at 300 K.The 4,6,7 which excites spins in the semiconductor with above-bandgap, circularly polarized light, and probes the induced bleaching with either the same or the opposite circularly polarized light ͑SCP or OCP, respectively͒. The pump and probe beams are pulsed, and by changing the time delay between the pump and probe, and comparing the SCP and OCP results, we measure the spin decay lifetime.…”

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confidence: 99%

Suppression of D’yakonov–Perel spin relaxation in InAs and InSb by n-type doping at 300 K

Murzyn

Pidgeon

Phillips

et al. 2003

Applied Physics Letters

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We have made direct pump-probe measurements of spin lifetimes in intrinsic and degenerate n-InAs at 300 K. In particular, we measure remarkably long spin lifetimes ( s ϳ1.6 ns) for near-degenerate epilayers of n-InAs. For intrinsic material, we determine s ϳ20 ps, in agreement with other workers. There are two main models that have been invoked for describing spin relaxation in narrow-gap semiconductors: the D'yakonov-Perel ͑DP͒ model and the Elliott-Yafet ͑EY͒ model. For intrinsic material, the DP model is believed to dominate in III-V materials above 77 K, in agreement with our results. We show that in the presence of strong n-type doping, the DP relaxation is suppressed both by the degeneracy condition and by electron-electron scattering, and that the EY model then dominates for the n-type material. We show that this same process is also responsible for a hitherto unexplained lengthening of s with n-type doping in our earlier measurements of n-InSb. Utilization of the electron spin has become a focus of interest in semiconductor electronics, or spintronics, in recent years, and it is important to realize a sufficiently long spin lifetime s to process information stored in the form of the polarization of spin ensembles.1-3 To find a way to control s , it is necessary to understand the spin relaxation mechanisms in both bulk and low-dimensional semiconductor structures which are designed so that spins can be appropriately confined and/or transferred. In contrast to GaAsbased systems, relatively little attention has been paid to InAs, even although it may be important in future spintronics applications. We previously measured spin lifetimes in narrow-gap semiconductors ͑NGSs͒, Hg 1Ϫx Cd x Te and InSb, at wavelengths between 4 and 10 m over the temperature range of 4 to 300 K. 4 We have now extended those measurements to include bulk epilayers of InAs as a function of doping at 300 K.The 4,6,7 which excites spins in the semiconductor with above-bandgap, circularly polarized light, and probes the induced bleaching with either the same or the opposite circularly polarized light ͑SCP or OCP, respectively͒. The pump and probe beams are pulsed, and by changing the time delay between the pump and probe, and comparing the SCP and OCP results, we measure the spin decay lifetime. The optical pulses for the experiment, carried out at the University of Surrey, were generated with a solidstate laser system that produces ϳ40 fs pulses from 2.5 to 11 m wavelength, with a repetition rate of 250 kHz and typical average power of 5 mW. The beams were focused onto the sample with spot sizes of approximately 100 m, and the transmitted probe light was detected with a liquid-nitrogencooled InSb photodiode.Results for the transmission change in the probe due to the pump are shown for sample IC313 in Fig. 1 for SCP and OCP configurations at a wavelength of 3.4 m; that is, just above the absorption edge. The data are in extremely good agreement with the results of other workers.6 Following Ref. 6, we plot the fractional difference in tr...

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“…Spin relaxation was attributed to Bychkov-Rashba spin splitting in these asymmetric wells, estimating the corresponding ប␣ BR in Eq. (88) to be around 1ϫ10 Ϫ14 eV m (Wilamowski and 84 Here is a list of selected references with useful data on s in GaAs/AlGaAs quantum wells: confinement energy dependence has been studied by Tackeuchi et al (1996); Britton et al (1998) ;Ohno, Terauchi, et al (1999; Endo et al (2000); Malinowski et al (2000); temperature dependence is treated by Wagner et al (1993); Ohno, Terauchi, et al (1999; Malinowski et al (2000); Adachi et al (2001); carrier concentration dependence is studied by Sandhu et al (2001); dependence on mobility is examined by Ohno, Terauchi, et al (1999); and dependence on magnetic field is studied by Zhitomirskii et al (1993). .…”

Section: Low-dimensional Semiconductor Structuresmentioning

confidence: 99%

Spintronics: Fundamentals and applications

2004

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Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics. CONTENTS

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Room temperature spin relaxation in GaAs/AlGaAs multiple quantum wells

Cited by 85 publications

References 14 publications

Investigation of transient linear and circular birefringence in metallic thin films

Investigation of transient linear and circular birefringence in metallic thin films

Suppression of D’yakonov–Perel spin relaxation in InAs and InSb by n-type doping at 300 K

Spintronics: Fundamentals and applications

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