Hole spin relaxation in InAs/GaAs quantum dot molecules

Segarra, Carlos; Climente, Juan I.; Rajadell, F.; Planelles, Josep

doi:10.1088/0953-8984/27/41/415301

Cited by 8 publications

(11 citation statements)

References 43 publications

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“…Coupling of spin to orbital degrees of freedom via the spin-orbit coupling (SOC) influences the carrier spectrum and could provide a channel of quantum coherent spin control 5 . On the other hand, it may mix spin configurations, which leads to spin relaxation and dephasing processes [6][7][8][9][10][11] . The lack of inversion symmetry, on the level of crystal lattice (bulk inversion asymmetry, BIA), in the shape of a nanostructure, or induced by external electric field (structure inversion asymmetry, SIA) gives rise to Dresselhaus and Rashba spin-orbit coupling, respectively 12 .…”

Section: Introductionmentioning

confidence: 99%

Spin-orbit coupling and spin relaxation of hole states in [001]- and [111]-oriented quantum dots of various geometry

Gawarecki

Krzykowski

2019

Phys. Rev. B

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We study the influence of spin-orbit coupling on the hole states in InAs/GaAs quantum dots grown on [001]-and [111]-oriented substrates belonging to symmetry point groups: C2v, C3v and D 2d . We investigate the impact of various spin-orbit mechanisms on the strength of coupling between s-and p-shell states, which is a significant spin-flip channel in quantum dots. We calculate spin relaxation rates between the states of lowest Zeeman doublet and show that the [111]-oriented structure offers one order of magnitude slower relaxation compared to the usual [001]-oriented self-assembled QD. The magnetic-field dependence of the hole states is calculated using multiband (up to 14 bands) k·p model. We identify the irreducible representations linked to the states and discuss the selection rules, which govern the avoided-crossing pattern in magnetic-field dependence of the energy levels. We show that dominant contribution to the coupling between some of these states comes from the shear strain. On the other hand, we demonstrate no coupling between s-and p-shell states in the [111]-oriented structure. arXiv:1809.09062v3 [cond-mat.mes-hall]

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Section: Introductionmentioning

confidence: 99%

Spin-orbit coupling and spin relaxation of hole states in [001]- and [111]-oriented quantum dots of various geometry

Gawarecki

Krzykowski

2019

Phys. Rev. B

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“…Hole spin mixing arises due to spin–orbit interactions within the valence band and requires symmetry breaking. Detailed descriptions of the origin of hole spin mixing and its magnitude under varying conditions can be found in the literature . The key concepts are that hole spins in QDs must be considered as spinors comprising both heavy and light components with

\pm 3 / 2

and

\pm 1 / 2

spin projections, respectively .…”

Section: Hole Spin Mixingmentioning

confidence: 99%

“…As always, however, no advantage comes for free. For example, the misalignment of the two QDs that is critical to hole spin mixing also leads to increased hole spin relaxation . Similarly, hole spin mixing leads to the formation of two molecular states (

| t ⟩

and

| u ⟩

in Figure ) that have opposite molecular orbital symmetry but similar optical coupling to the qubit basis states.…”

Section: Hole Spin Mixingmentioning

confidence: 99%

“…Detailed descriptions of the origin of hole spin mixing and its magnitude under varying conditions can be found in the literature. [193][194][195] The key concepts are that hole spins in QDs must be considered as spinors comprising both heavy and light components with ±3∕2 and ±1∕2 spin projections, respectively. [94] Every hole state contains some contribution from all four of these hole spin projections, but the spinors describing the two ground states of the hole in a QD are dominated by the contributions from the ±3∕2 components.…”

Section: Hole Spin Mixingmentioning

confidence: 99%

“…For example, the misalignment of the two QDs that is critical to hole spin mixing also leads to increased hole spin relaxation. [195] Similarly, hole spin mixing leads to the formation of two molecular states (|t⟩ and |u⟩ in Figure 19) that have opposite molecular orbital symmetry but similar optical coupling to the qubit basis states. CPT methods for all-optical spin rotation based on the target (|t⟩) optically excited state are degraded by off-resonant coupling to the unwanted (|u⟩) state.…”

Section: Hole Spin Mixingmentioning

confidence: 99%

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Self‐Assembled InAs/GaAs Coupled Quantum Dots for Photonic Quantum Technologies

Jennings

Wickramasinghe

et al. 2019

Adv Quantum Tech

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Coupled quantum dots (CQDs) that consist of two InAs QDs stacked along the growth direction and separated by a relatively thin tunnel barrier have been the focus of extensive research efforts. The expansion of available states enabled by the formation of delocalized molecular wavefunctions in these systems has led to significant enhancement of the already substantial capabilities of single QD systems and have proven to be a fertile platform for studying light–matter interactions, from semi‐classical to purely quantum phenomena. Observations unique to CQDs, including tunable g‐factors and radiative lifetimes, in situ control of exchange interactions, coherent phonon effects, manipulation of multiple spins, and nondestructive spin readout, along with possibilities such as quantum‐to‐quantum transduction with error correction and multipartite entanglement, open new and exciting opportunities for CQD‐based photonic quantum technologies. This review is focused on recent CQD work, highlighting aspects where CQDs provide a unique advantage and with an emphasis on results relevant to photonic quantum technologies.

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Spin–orbit-induced hole spin relaxation in a quantum dot molecule: the effect of s-p coupling

Kawa¹,

Machnikowski²

2019

J. Phys.: Condens. Matter

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We study the effect of the coupling between the hole s shell of one quantum dot and the p shell in the other dot forming a quantum dot molecule on the spin relaxation between the sublevels of the hole s state. Using an effective model that captures the spin-orbit effects in the p shell irrespective of their origin, we show that the strong spin mixing in the p shell can be transferred to the s shell of the other dot, leading to enhanced spin relaxation in a certain energy range around the s-p resonance if the dots are misaligned and the magnetic field is tilted from the sample plane. arXiv:1902.09161v1 [cond-mat.mes-hall]

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Hole spin relaxation in InAs/GaAs quantum dot molecules

Cited by 8 publications

References 43 publications

Spin-orbit coupling and spin relaxation of hole states in [001]- and [111]-oriented quantum dots of various geometry

Spin-orbit coupling and spin relaxation of hole states in [001]- and [111]-oriented quantum dots of various geometry

Self‐Assembled InAs/GaAs Coupled Quantum Dots for Photonic Quantum Technologies

Spin–orbit-induced hole spin relaxation in a quantum dot molecule: the effect of s-p coupling

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