Spin-lattice relaxation in Si quantum dots

Glavin, B. A.

doi:10.1103/physrevb.68.045308

Cited by 26 publications

(57 citation statements)

References 14 publications

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“…34,35,50,53,54,[56][57][58][59][60][61][62][63][64][65][66][67] Our work completes these findings by a global, quantitative understanding of two-electron lateral silicon double quantum dots. We investigate the spin-orbit and hyperfine-induced relaxation rate as a function of interdot coupling, detuning, and the magnitude and orientation of the external magnetic field for zero and finite temperatures, and for natural and isotopically purified silicon.…”

Section: Introductionsupporting

confidence: 70%

Theory of spin relaxation in two-electron laterally coupled Si/SiGe quantum dots

2012

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Highly accurate numerical results of phonon-induced two-electron spin relaxation in silicon double quantum dots are presented. The relaxation, enabled by spin-orbit coupling and the nuclei of 29 Si (natural or purified abundance), is investigated for experimentally relevant parameters, the interdot coupling, the magnetic field magnitude and orientation, and the detuning. We calculate relaxation rates for zero and finite temperatures (100 mK), concluding that our findings for zero temperature remain qualitatively valid also for 100 mK. We confirm the same anisotropic switch of the axis of prolonged spin lifetime with varying detuning as recently predicted in GaAs. Conditions for possibly hyperfine-dominated relaxation are much more stringent in Si than in GaAs. For experimentally relevant regimes, the spin-orbit coupling, although weak, is the dominant contribution, yielding anisotropic relaxation rates of at least two orders of magnitude lower than in GaAs.

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Section: Introductionsupporting

confidence: 70%

Theory of spin relaxation in two-electron laterally coupled Si/SiGe quantum dots

2012

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“…H bulk one−valley represents a sum over the six minima in the bulk case, but in a lateral quantum dot the dominant contribution comes only from the ±z minima and was determined by Glavin and Kim [17] to be…”

Section: A Bulk Spin-flip Mechanismsmentioning

confidence: 99%

Relaxation of excited spin, orbital, and valley qubit states in ideal silicon quantum dots

2014

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We expand on previous work that treats relaxation physics of low-lying excited states in ideal, single electron, silicon quantum dots in the context of quantum computing. These states are of three types: orbital, valley, and spin. The relaxation times depend sensitively on system parameters such as the dot size and the external magnetic field. Generally, however, orbital relaxation times are short in strained silicon (10 −7 to 10 −12 s), spin relaxation times are long, (10 −6 to 1 s), while valley relaxation times are expected to lie in between. The focus is on relaxation due to emission or absorption of phonons, but for spin relaxation we also consider competing mechanisms such as charge noise. Where appropriate, comparison is made to reference systems such as quantum dots in III-V materials and silicon donor states. The phonon bottleneck effect is shown to be rather small in the silicon dots of interest. We compare the theoretical predictions to some recent spin relaxation experiments and comment on the possible effects of non-ideal dots.

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“…Also the spin relaxation due to the modulation of electron g-factor by the phonon-induced strain was investigated. 67 Experimentally the rates were measured on quantum dot ensembles 68,69 and on a many-electron quantum dot. 70,71 We obtain the spin relaxation rates non-perturbatively, using exact numerical diagonalization, for a wide range of magnetic fields and interdot coupling.…”

Section: -15mentioning

confidence: 99%

Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots

2011

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We investigate the spin relaxation induced by acoustic phonons in the presence of spin-orbit interactions in single electron Si/SiGe lateral coupled quantum dots. The relaxation rates are computed numerically in single and double quantum dots, in in-plane and perpendicular magnetic fields. The deformation potential of acoustic phonons is taken into account for both transverse and longitudinal polarizations and their contributions to the total relaxation rate are discussed with respect to the dilatation and shear potential constants. We find that in single dots the spin relaxation rate scales approximately with the seventh power of the magnetic field, in line with a recent experiment. In double dots the relaxation rate is much more sensitive to the dot spectrum structure, as it is often dominated by a spin hot spot. The anisotropy of the spin-orbit interactions gives rise to easy passages, special directions of the magnetic field for which the relaxation is strongly suppressed. Quantitatively, the spin relaxation rates in Si are typically 2 orders of magnitude smaller than in GaAs due to the absence of the piezoelectric phonon potential and generally weaker spinorbit interactions.

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Spin-lattice relaxation in Si quantum dots

Cited by 26 publications

References 14 publications

Theory of spin relaxation in two-electron laterally coupled Si/SiGe quantum dots

Theory of spin relaxation in two-electron laterally coupled Si/SiGe quantum dots

Relaxation of excited spin, orbital, and valley qubit states in ideal silicon quantum dots

Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots

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