Impact of artificial lateral quantum confinement on exciton-spin relaxation in a two-dimensional GaAs electronic system

Kiba, Takayuki; Tanaka, Toru; Tamura, Yasuaki; Higo, Akio; Clifford, Thomas; Samukawa, Seiji; Murayama, Akihiro

doi:10.1063/1.4897958

Cited by 6 publications

(2 citation statements)

References 24 publications

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“…This enables us to investigate effects of the lateral quantum confinement of carriers or excitons on spin dynamics. In fact, we have recently reported a significant suppression of exciton-spin relaxation in GaAs NDs by observing circularly polarized transient photoluminescence (PL) [5]. In this work, we expand on these methods to study transient optical Kerr effects under magnetic fields in GaAs NDs, which enables us to elucidate more detailed factors responsible for spin dynamics, such as the g-factor and relaxation of precession, i.e., spin dephasing.…”

Section: Introductionmentioning

confidence: 95%

Electron g-factor and spin decoherence in GaAs quantum nanodisks fabricated by fully top-down lithography

Tanaka

Kiba

Higo

et al. 2015

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 95%

Electron g-factor and spin decoherence in GaAs quantum nanodisks fabricated by fully top-down lithography

Tanaka

Kiba

Higo

et al. 2015

Journal of Crystal Growth

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“…2(b)]. 17) The QNDs were 8 nm in thickess and approximately 7 nm in diameter. If the thickness is smaller than 8 nm, the quantum confinement effect becomes weak.…”

Section: Methodsmentioning

confidence: 99%

Optical properties of quantum energies in GaAs quantum nanodisks produced using a bio-nanotemplate and a neutral beam etching technique

Ohori¹,

Fukuyama²,

Clifford³

et al. 2016

Jpn. J. Appl. Phys.

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We demonstrated that the lattice-matched GaAs quantum nanodisks (QNDs) embedded in an AlGaAs matrix were fabricated by our original top-down nanoprocess. Lattice-matched GaAs QNDs are very attractive in quantum cryptography because the spin relaxation time of QNDs might be longer than that of strained quantum dots. Quantum levels of QNDs were investigated by the photoluminescence (PL) technique. The minimum diameter and thickness of QNDs were 7 and 8 nm, respectively. PL peaks of QNDs at 1.64 and 1.66 eV were observed to be higher than that of multiple quantum wells (MQWs) observed at 1.57 eV. It is suggested that these peaks are due to the diameter distribution of QNDs. The calculated quantum levels were in good agreement with the present experimental results. The observation of the PL peaks from QNDs demonstrates that the quantum level is strongly confined not only in the perpendicular direction but also in the lateral direction.

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Electric field control of spin polarity in spin injection into InGaAs quantum dots from a tunnel-coupled quantum well

Chen

Hiura

Takayama

et al. 2019

Applied Physics Letters

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Electric field control of spin polarity in spin injection into InGaAs quantum dots (QDs) from a tunnel-coupled quantum well (QW) was studied. The degree of freedom of the spin state in high-density QDs will play an important role in semiconductor spintronics such as a spin-functional optical device, where it is crucial to establish spin injection and manipulation by electric fields. To solve this subject in a layered device structure, electric field effects on spin injection from a 2-dimensional QW into 0-dimensional QDs were studied. Spin-polarized electrons were photo-excited in a QW and then injected into QDs via spin-conserving tunneling. After the injection, parallel spin states to the initial spin direction in the spin reservoir of QW were observed in QDs as a result of efficient spin injection, by circularly polarized photoluminescence indicating spin states in the QDs. Moreover, reversal of spin polarity was clearly observed at QD ground states, depending on the electric fields applied along the QD-QW growth direction. The tunneling rate of an electron is different from that of a hole and largely depends on the electric field, owing to electric field induced modifications of the coupled QD-QW potential. This results in negative trions in the QDs with anti-parallel spins to the initial ones in the QW, which is evidently supported by a significant effect of p-doping. The polarization degrees of both spin polarities can be optimized by excitation-spin density, in addition to the electric field strength.

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Impact of artificial lateral quantum confinement on exciton-spin relaxation in a two-dimensional GaAs electronic system

Cited by 6 publications

References 24 publications

Electron g-factor and spin decoherence in GaAs quantum nanodisks fabricated by fully top-down lithography

Electron g-factor and spin decoherence in GaAs quantum nanodisks fabricated by fully top-down lithography

Optical properties of quantum energies in GaAs quantum nanodisks produced using a bio-nanotemplate and a neutral beam etching technique

Electric field control of spin polarity in spin injection into InGaAs quantum dots from a tunnel-coupled quantum well

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