Acoustic charge and spin transport in GaAs quantum wires

Alsina, F.; Stotz, J. A. H.; Hey, R.; Jahn, U.; Santos, P. V.

doi:10.1002/pssc.200779268

Cited by 5 publications

(7 citation statements)

References 9 publications

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“…Similar ambipolar transport experiments were demonstrated in µm-sized electrostatically defined wires [15] as well as sub-µm sidewall QWRs fabricated by epitaxially overgrowing shallow ridges on GaAs(113)A substrates [16,17]. Long acoustic driven transport distances for charge carriers have been achieved in overgrown QWRs (up to 50 µm) [18]. Their optical and transport properties were found, however, to be very sensitive to potential fluctuations along the transport path.…”

Section: Introductionsupporting

confidence: 63%

“…These transport distances are much shorter than the ones reported for acoustic transport in electrostatic wires [20]. It was argued that the acoustic spin transport length is limited by Elliot-Yafet (EY) scattering due to the large density of scattering centers along the QWR axis [18]. These findings call for fabrication processes yielding narrow QWRs with small potential fluctuations.…”

Section: Introductionmentioning

confidence: 90%

“…The one-directional motion of carriers in QWRs also provides a pathway to reduce spin dephasing due to the Dyakonov-Perel mechanism [2,3]. Alsina et al [18] investigated spin transport in sidewall QWRs grown on GaAs(113)A substrates with a width of 50 nm. Whereas the narrow width should lead to a long spin relaxation time and, correspondingly, long spin transport lengths, the observed acoustic spin transport length was limited to distances of only approx.…”

Section: Introductionmentioning

confidence: 99%

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Sidewall Quantum Wires on GaAs (001) Substrates

et al. 2019

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We study the structural, optical, and transport properties of sidewall quantum wires on GaAs(001) substrates. The QWRs are grown by molecular beam epitaxy (MBE) on GaAs(001) substrates prepatterned with shallow ridges. They form as a consequence of material accumulation on the sidewalls of the ridges during the overgrowth of a quantum well (QW) on the patterned surface. The QWRs are approximately 200 nm-wide and have emission energies red-shifted by 27 meV with respect to the surrounding QW. Spatially resolved spectroscopic photoluminencence studies indicate that the QW thickness reduces around the QWRs, thus creating a 4 meV energy barrier for the transfer of carriers from the QW to the QWR. We show that the QWRs act as efficient channels for the transport of optically excited electrons and holes over tens of µm by a high-frequency surface acoustic wave (SAW). These results demonstrate the feasibility of efficient ambipolar transport in QWRs with sub-micrometer dimensions, photolithographically defined on GaAs substrates.

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Section: Introductionsupporting

confidence: 63%

Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Sidewall Quantum Wires on GaAs (001) Substrates

et al. 2019

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“…A possible explanation lies on the nature of the lateral confinement potential: while purely electrostatic for DQDs, it is imposed by structural interfaces in the QWRs. Spin dephasing due to frequent scattering events at these interfaces (known as Elliot-Yafet processes [39]), as previously postulated for QWRs, [14,40] as well as interface-related SO fields may thus limit s in structural channels. A further remarkable experimental result is the weak SAW amplitude dependence of the spin precession rate Ω SO for transport in QW structures as compared to QWRs and DQDs [cf.…”

Section: Dimensionality Effects On the Spin Dynamicsmentioning

confidence: 85%

Flying electron spin control gates

Helgers,

Stotz,

Sanada

et al. 2021

Preprint

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The control of "flying" (or moving) spin qubits is an important functionality for the manipulation and exchange of quantum information between remote locations on a chip. Typically, gates based on electric or magnetic fields provide the necessary perturbation for their control either globally or at well-defined locations. Here, we demonstrate the dynamic control of moving electron spins via contactless gates that move together with the spin. The concept is realized using electron spins trapped and transported by moving potential dots defined by a surface acoustic wave (SAW). The SAW strain at the electron trapping site, which is set by the SAW amplitude, acts as a contactless, tunable gate that controls the precession frequency of the flying spins via the spin-orbit interaction. We show that the degree of precession control in moving dots exceeds previously reported results for unconstrained transport by an order of magnitude and is well accounted for by a theoretical model for the strain contribution to the spin-orbit interaction. This flying spin gate permits the realization of an acoustically driven optical polarization modulator based on electron spin transport, a key element for on-chip spin information processing with a photonic interface.

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“…Whereas carrier as well as spin transport has been reported for GaAs quantum wires [7]; adequate results for (In,Ga)As-based structures are still not satisfying. Therefore, improvement of the quality of wire-like structures is highly desired for several reasons.…”

Section: Introductionmentioning

confidence: 98%