Electrical tuning of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>g</mml:mi></mml:math>factor of single self-assembled quantum dots

Nakaoka, Toshihiro; Tarucha, Seigo; Arakawa, Yasuhiko

doi:10.1103/physrevb.76.041301

Cited by 43 publications

(50 citation statements)

References 21 publications

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“…This complies with our theoretical prediction: as these cylindrical quantum dots have a large aspect ratio, the orbital current can encircle a much larger area when the orbital moment is along the symmetry axis than when it is directed in-plane. Although the anisotropy of the electron g factor has been measured experimentally in quantum wells [45] and quantum dots [29][30][31][35][36][37], the reported anisotropies have been generally small and were not explained using this simple geometrical argument. We point out that the anisotropy makes it possible to size-engineer separately g x e and g z e close to zero, where an additional electric field can then be used to change the sign of the g factor.…”

Section: B Electron G Factorsmentioning

confidence: 99%

“…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. As quantum confinement and strain affect the g tensor, it is generally found that the inhomogeneous distribution of quantum dots leads to different g factors and electric-field sensitivities for each individually measured quantum dot.…”

Section: Introductionmentioning

confidence: 99%

“…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%

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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: B Electron G Factorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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“…Confinement has been shown to quench this magnetic moment, even for nanostructures with spherical symmetry [1,[4][5][6], to a much greater degree than expected from confinement-induced shifts in semiconductor band gap, spin-orbit splitting, and masses. Confinement-induced effects on the magnetic moment μ also directly modify the temporal evolution of a spin in a magnetic field [7][8][9][10][11][12][13][14][15] by slowing or speeding precession, or through forms of electrically driven resonance such as g-tensor modulation resonance [16]. These modifications have been suggested as means to manipulate the spins for quantum computation [17,18].…”

Section: Introductionmentioning

confidence: 99%

Geometric and compositional influences on spin-orbit induced circulating currents in nanostructures

et al. 2014

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Circulating orbital currents, originating from the spin-orbit interaction, are calculated for semiconductor nanostructures in the shape of spheres, disks, spherical shells, and rings for the electron ground state with spin oriented along a symmetry axis. The currents and resulting orbital and spin magnetic moments, which combine to yield the effective electron g factor, are calculated using a recently introduced formalism that allows the relative contributions of different regions of the nanostructure to be identified at zero magnetic field. For all these spherically or cylindrically symmetric hollow or solid nanostructures, independent of material composition and whether the boundary conditions are hard or soft, the dominant orbital current originates from intermixing of valence-band states in the electron ground state, circulates within the nanostructure, and peaks approximately halfway between the center and edge of the nanostructure in the plane perpendicular to the spin orientation. For a specific material composition and confinement character, the confinement energy and orbital moment are determined by a single size-dependent parameter for spherically symmetrical nanostructures, whereas they can be independently tuned for cylindrically symmetric nanostructures.

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“…8 However, very weak effects are typically observed for QDs. 9 Recently, we reported electrically tunable exciton g factors in (Ga)InAs self-assembled QDs grown using the partially covered island (PCI) method. However, due to a lack of information on the microscopic shape and In-composition profile, we could not identify the mechanism responsible for the tuning.…”

mentioning

confidence: 99%

Observation and explanation of strong electrically tunable excitongfactors in composition engineered In(Ga)As quantum dots

et al. 2011

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Electrical tuning of thegfactor of single self-assembled quantum dots

Cited by 43 publications

References 21 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

Geometric and compositional influences on spin-orbit induced circulating currents in nanostructures

Observation and explanation of strong electrically tunable excitongfactors in composition engineered In(Ga)As quantum dots

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