Nucleus-mediated spin-flip transitions in GaAs quantum dots

Erlingsson, Sigurdur I.; Nazarov, Yuli V.

doi:10.1103/physrevb.64.195306

Cited by 165 publications

(203 citation statements)

References 30 publications

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“…Finally, at low magnetic fields the relaxation is believed to be dominated by the hyperfine interaction between the electron and nuclei of the host material. 4,5 …”

Section: ͑16͒mentioning

confidence: 99%

“…At low magnetic fields ͑say, tens of gauss͒, the relaxation proceeds via hyperfine coupling of the electron spin with the lattice or impurity nuclei. [4][5][6] On the other hand, at higher fields ͑Teslas͒ the relaxation is due to phonon-induced spin-flip transitions. [7][8][9][10][11][12][13][14][15][16][17][18][19] These are allowed due to the presence of spin-orbit coupling.…”

Section: Introductionmentioning

confidence: 99%

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Orbital and spin relaxation in single and coupled quantum dots

Stano

Fabian

2006

Phys. Rev. B

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Phonon-induced orbital and spin relaxation rates of single electron states in lateral single and double quantum dots are obtained numerically for realistic materials parameters. The rates are calculated as a function of magnetic field and interdot coupling, at various field and quantum dot orientations. It is found that orbital relaxation is due to deformation potential phonons at low magnetic fields, while piezoelectric phonons dominate the relaxation at high fields. Spin relaxation, which is dominated by piezoelectric phonons, in single quantum dots is highly anisotropic due to the interplay of the Bychkov-Rashba and Dresselhaus spin-orbit couplings. Orbital relaxation in double dots varies strongly with the interdot coupling due to the cyclotron effects on the tunneling energy. Spin relaxation in double dots has an additional anisotropy due to anisotropic spin hot spots which otherwise cause giant enhancement of the rate at useful magnetic fields and interdot couplings. Conditions for the absence of the spin hot spots in in-plane magnetic fields ͑easy passages͒ and perpendicular magnetic fields ͑weak passages͒ are formulated analytically for different growth directions of the underlying heterostructure. It is shown that easy passages disappear ͑spin hot spots reappear͒ if the double dot system loses symmetry by an xy-like perturbation.

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“…Finally, at low magnetic fields the relaxation is believed to be dominated by the hyperfine interaction between the electron and nuclei of the host material. 4,5 …”

Section: ͑16͒mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Orbital and spin relaxation in single and coupled quantum dots

Stano

Fabian

2006

Phys. Rev. B

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“…At liquid helium temperatures the characteristic time of spin relaxation for electrons on phonons is about seconds, whereas for nuclei it ranges from days to years 1,6,7,8 . The direct transfer of spin angular momentum to the crystal by the dipole-dipole interaction between nuclear spins is the main mechanism for the relaxation of the spin polarization.…”

Section: A Conservation Laws and Thermodynamic Potentials Of The Enssmentioning

confidence: 99%

“…The relaxation of ς is caused by the flipping of the electron spin. The energy of this transition, Ω, cannot be taken from the nuclear spin system as Ω ≫ ω L , but is due to phonon-scattering instead 6,7,8 . A sketch of connections between ENSS parameters and their relaxations is presented in Fig.…”

Section: A Conservation Laws and Thermodynamic Potentials Of The Enssmentioning

confidence: 99%

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Long-term dynamics of the electron-nuclear spin system of a semiconductor quantum dot

et al. 2010

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A quasi-classical theoretical description of polarization and relaxation of nuclear spins in a quantum dot with one resident electron is developed for arbitrary mechanisms of electron spin polarization. The dependence of the electron-nuclear spin dynamics on the correlation time τc of electron spin precession, with frequency Ω, in the nuclear hyperfine field is analyzed. It is demonstrated that the highest nuclear polarization is achieved for a correlation time close to the period of electron spin precession in the nuclear field. For these and larger correlation times, the indirect hyperfine field, which acts on nuclear spins, also reaches a maximum. This maximum is of the order of the dipole-dipole magnetic field that nuclei create on each other. This value is non-zero even if the average electron polarization vanishes. It is shown that the transition from short correlation time to Ωτc 1 does not affect the general structure of the equation for nuclear spin temperature and nuclear polarization in the Knight field, but changes the values of parameters, which now become functions of Ωτc. For correlation times larger than the precession time of nuclei in the electron hyperfine field, it is found that three thermodynamic potentials (χ, ξ, ς) characterize the polarized electron-nuclear spin system. The values of these potentials are calculated assuming a sharp transition from short to long correlation times, and the relaxation mechanisms of these potentials are discussed. The relaxation of the nuclear spin potential is simulated numerically showing that high nuclear polarization decreases relaxation rate.

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Quantum Computing with Spins in Solids

Coish

Loss

2007

Handbook of Magnetism and Advanced Magnetic Materials

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The ability to perform high-precision one-and two-qubit operations is sufficient for universal quantum computation. For the Loss-DiVincenzo proposal to use single electron spins confined to quantum dots as qubits, it is therefore sufficient to analyze only single-and coupled double-dot structures, since the strong Heisenberg exchange coupling between spins in this proposal falls off exponentially with distance and long-ranged dipolar coupling mechanisms can be made significantly weaker. This scalability of the Loss-DiVincenzo design is both a practical necessity for eventual applications of multi-qubit quantum computing and a great conceptual advantage, making analysis of the relevant components relatively transparent and systematic. We review the Loss-DiVincenzo proposal for quantum-dot-confined electron spin qubits, and survey the current state of experiment and theory regarding the relevant single-and double-quantum dots, with a brief look at some related alternative schemes for quantum computing.

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Nucleus-mediated spin-flip transitions in GaAs quantum dots

Cited by 165 publications

References 30 publications

Orbital and spin relaxation in single and coupled quantum dots

Orbital and spin relaxation in single and coupled quantum dots

Long-term dynamics of the electron-nuclear spin system of a semiconductor quantum dot

Quantum Computing with Spins in Solids

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