Fast preparation of a single-hole spin in an InAs/GaAs quantum dot in a Voigt-geometry magnetic field

Godden, T. M.; Quilter, J. H.; Ramsay, Andrew J.; Wu, Yanwen; Brereton, Peter; Luxmoore, I. J.; Puebla, Jorge; Fox, A. M.; Skolnick, M. S.

doi:10.1103/physrevb.85.155310

Cited by 35 publications

(44 citation statements)

References 49 publications

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“…Experimental efforts have been made to characterize the g factors (i.e., components of the g tensor) of excitons [21][22][23][24][25][26], and of individual electron and holes [27][28][29][30][31][32][33][34][35][36] confined in quantum dots. Also, electric control over g factors has been shown [25,29,33,[35][36][37]; in particular, it was found that the hole g factor is much more sensitive to an electric field than the electron g factor.…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of electron and holegtensors of quantum dots: An intuitive picture based on spin-correlated orbital currents

et al. 2016

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Koenraad, P. M. (2016). Anisotropy of electron and hole g tensors of quantum dots: An intuitive picture based on spin-correlated orbital currents. Physical Review B, 93(3), [035311]. DOI: 10.1103/PhysRevB.93.035311 General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Using single spins in semiconductor quantum dots as qubits requires full control over the spin state. As the g tensor provides the coupling in a Hamiltonian between a spin and an external magnetic field, a deeper understanding of the g tensor underlies magnetic-field control of the spin. The g tensor is affected by the presence of spin-correlated orbital currents, of which the spatial structure has been recently clarified. Here we extend that framework to investigate the influence of the shape of quantum dots on the anisotropy of the electron g tensor. We find that the spin-correlated orbital currents form a simple current loop perpendicular to the magnetic moment's orientation. The current loop is therefore directly sensitive to the shape of the nanostructure: for cylindrical quantum dots, the electron g-tensor anisotropy is mainly governed by the aspect ratio of the dots. Through a systematic experimental study of the size dependence of the separate electron and hole g tensors of InAs/InP quantum dots, we have validated this picture. Moreover, we find that through size engineering it is possible to independently change the sign of the in-plane and growth direction electron g factors. The hole g tensor is found to be strongly anisotropic and very sensitive to the radius and elongation. The comparable importance of itinerant and localized currents to the hole g tensor complicates the analysis relative to the electron g tensor.

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Section: Introductionmentioning

confidence: 99%

Anisotropy of electron and holegtensors of quantum dots: An intuitive picture based on spin-correlated orbital currents

et al. 2016

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“…For all associated quantum protocols the high fidelity initialization of single spin states that can be generated on-demand on ultra short timescales [13][14][15] and the reliable storage of the spin state is crucial 16,17 . The initialization of single spins can either be performed by spin-pumping of a charged QD 14 or by tunneling ionization of photo-generated excitons 13,[18][19][20][21] . While spin pumping is very convenient since it requires only a single continuous wave laser, it is rather slow with reported initialization fidelities of > 90% after ∼ 1ns.…”

Section: Introductionmentioning

confidence: 99%

Controlled tunneling-induced dephasing of Rabi rotations for high-fidelity hole spin initialization

et al. 2015

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We report the sub-picosecond initialization of a single heavy hole spin in a self-assembled quantum dot with > 98.5% fidelity and without external magnetic field. Using an optically addressable charge and spin storage device we tailor the relative electron and hole tunneling escape timescales from the dot and simultaneously achieve high-fidelity initialization, long hole storage times and high efficiency readout via a photocurrent signal. We measure electric field-dependent Rabi oscillations of the neutral and charged exciton transitions in the ultrafast tunneling regime and demonstrate that tunneling induced dephasing (TID) of excitonic Rabi rotations is the major source for the intensity damping of Rabi oscillations in the low Rabi frequency, low temperature regime. Our results are in very good quantitative agreement with quantum-optical simulations revealing that TID can be used to precisely measure tunneling escape times and extract changes in the Coulomb binding energies for different charge configurations of the quantum dot. Finally, we demonstrate that for sub-picosecond electron tunneling escape TID of a coherently driven exciton transition facilitates ultrafast hole spin initialization with near-unity fidelity.

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“…[3,4] Additionally, the p-type symmetry of the valence band orbitals causes a weak hyperfine interaction with the lattice nuclei, thus giving rise to decoherence times potentially longer than those of electron spins. [5,6,7,8,9,10,11] This has enabled successful hole spin initialization [12] and coherent control [10,13]. Double quantum dots (DQDs) are a natural extension which should facilitate the use of independent optical transitions for spin preparation, manipulation and readout, [14] as well as the scalability towards multiple qubit architectures.…”

Section: Introductionmentioning

confidence: 99%

Hole spin relaxation in InAs/GaAs quantum dot molecules

Segarra

Climente

Rajadell

et al. 2015

J. Phys.: Condens. Matter

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Abstract. We calculate the spin-orbit induced hole spin relaxation between Zeeman sublevels of vertically stacked InAs quantum dots. The widely used Luttinger-Kohn Hamiltonian, which considers coupling of heavy-and light-holes, reveals that hole spin lifetimes (T 1 ) of molecular states significantly exceed those of single quantum dot states. However, this effect can be overcome when cubic Dresselhaus spin-orbit interaction is strong. Misalignment of the dots along the stacking direction is also found to be an important source of spin relaxation.

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Fast preparation of a single-hole spin in an InAs/GaAs quantum dot in a Voigt-geometry magnetic field

Cited by 35 publications

References 49 publications

Anisotropy of electron and holegtensors of quantum dots: An intuitive picture based on spin-correlated orbital currents

Anisotropy of electron and holegtensors of quantum dots: An intuitive picture based on spin-correlated orbital currents

Controlled tunneling-induced dephasing of Rabi rotations for high-fidelity hole spin initialization

Hole spin relaxation in InAs/GaAs quantum dot molecules

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