Singlet-triplet relaxation in SiGe/Si/SiGe double quantum dots

Abstract

We study the singlet-triplet relaxation due to the spin-orbit coupling assisted by the electron-phonon scattering in two-electron SiGe/Si/SiGe double quantum dots in the presence of an external magnetic field in either Faraday or Voigt configuration. By explicitly including the electron-electron Coulomb interaction and the valley splitting induced by the interface scattering, we employ the exact-diagonalization method to obtain the energy spectra and the eigenstates. Then we calculate the relaxation rates with the Fermi golden rule. We find that the transition rates can be effectively tuned by varying the external magnetic field and the interdot distance. Especially in the vicinity of the anticrossing point, the transition rates show intriguing features. We also investigate the electric-field dependence of the transition rates, and find that the transition rates are almost independent of the electric field. This is of great importance in the spin manipulation since the lifetime remains almost the same during the change of the qubit configuration from $(1,1)$ to $(2,0)$ by the electric field.

9 pages, 8 figures

References in corpus (10)

• Pauli-Spin-Blockade Transport through a Silicon Double Quantum Dot
• Physical mechanisms of interface-mediated intervalley coupling in Si
• Electric field effect on electron spin splitting in SiGe/Si quantum wells
• Hubbard model description of silicon spin qubits: charge stability diagram and tunnel coupling in Si double quantum dots
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• Fast tunnel rates in Si/SiGe one-electron single and double quantum dots
• Singlet-triplet relaxation in multivalley silicon single quantum dots
• Triplet-singlet relaxation in semiconductor single and double quantum dots

Cited by in corpus (13)

• Silicon Quantum Electronics
• A fast "hybrid" silicon double quantum dot qubit
• Single-shot measurement of triplet-singlet relaxation in a Si/SiGe double quantum dot
• Spin dynamics in a strongly driven system: very slow Rabi oscillations
• Theory of Spin Relaxation in Two-Electron Lateral Coupled Quantum Dots
• Theory of Spin Relaxation in Two-Electron Lateral Coupled Si/SiGe Quantum Dots
• Coherent electrical rotations of valley states in Si quantum dots using the phase of the valley-orbit coupling
• Phonon-assisted relaxation and decoherence of singlet-triplet qubits in Si/SiGe quantum dots
• Interacting holes in Si and Ge double quantum dots: from a multiband approach to an effective-spin picture
• Energy spectra of three electrons in Si/SiGe single and vertically coupled double quantum dots
• Energy spectra of three electrons in SiGe/Si/SiGe laterally coupled triple quantum dots
• Inter- and intra-band Coulomb interactions between holes in silicon nanostructures
• Defect engineering spin centers in interacting many-body Su-Schrieffer-Heeger chains