Quadrupolar and anisotropy effects on dephasing in two-electron spin qubits in GaAs

Abstract

Understanding the decoherence of electron spins in semiconductors due to their interaction with nuclear spins is of fundamental interest as they realize the central spin model and of practical importance for using electron spins as qubits. Interesting effects arise from the quadrupolar interaction of nuclear spins with electric field gradients, which have been shown to suppress diffusive nuclear spin dynamics. One might thus expect them to enhance electron spin coherence. Here we show experimentally that for gate-defined GaAs quantum dots, quadrupolar broadening of the nuclear Larmor precession can also reduce electron spin coherence due to faster decorrelation of transverse nuclear fields. However, this effect can be eliminated for appropriate field directions. Furthermore, we observe an additional modulation of spin coherence that can be attributed to an anisotropic electronic $g$-tensor. These results complete our understanding of dephasing in gated quantum dots and point to mitigation strategies. They may also help to unravel unexplained behaviour in related systems such as self-assembled quantum dots and III-V nanowires.

6 pages, 4 figures

References in corpus (12)

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• Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization
• Theory of electron spin decoherence by interacting nuclear spins in a quantum dot
• Fast Single-Charge Sensing with an rf Quantum Point Contact
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• Pure quantum dephasing of a solid state electron spin qubit in a large nuclear spin bath coupled by long-range hyperfine-mediated interactions
• Dynamics of Quantum Dot Nuclear Spin Polarization Controlled by a Single Electron
• Universal pulse sequence to minimize spin dephasing in the central spin decoherence problem
• Semiclassical dynamics and long time asymptotics of the central-spin problem in a quantum dot
• Quadrupolar induced suppression of nuclear spin bath fluctuations in self-assembled quantum dots
• Wavefunction considerations for the central spin decoherence problem in a nuclear spin bath
• Characterization of S-T${}_{+}$ Transition Dynamics via Correlation Measurements

Cited by in corpus (25)

• Quantum many-body theory for electron spin decoherence in nanoscale nuclear spin baths
• Environmental noise spectroscopy with qubits subjected to dynamical decoupling
• Probing low noise at the MOS interface with a spin-orbit qubit
• Notch filtering the nuclear environment of a spin qubit
• Spectrum of the Nuclear Environment for GaAs Spin Qubits
• Ideal refocusing of an optically active spin qubit under strong hyperfine interactions
• Closed-loop control of a GaAs-based singlet-triplet spin qubit with 99.5% gate fidelity and low leakage
• Tuning methods for semiconductor spin--qubits
• Controllable freezing of the nuclear spin bath in a single-atom spin qubit
• Witnessing quantum correlations in a nuclear ensemble via an electron spin qubit
• Dynamical suppression of fluctuations in an interacting nuclear spin bath of a self-assembled quantum dot using multiple pulse nuclear magnetic resonance
• Magnetic Gradient Fluctuations from Quadrupolar ${}^{73}$Ge in Si/SiGe Exchange-Only Qubits
• Transfer of a quantum state from a photonic qubit to a gate-defined quantum dot
• Cross-calibration of GaAs deformation potentials and gradient-elastic tensors using photoluminescence and nuclear magnetic resonance spectroscopy in GaAs/AlGaAs quantum dot structures
• G-factor of electrons in gate-defined quantum dots in a strong in-plane magnetic field
• Coherent Charge Oscillations in a Bilayer Graphene Double Quantum Dot
• Measurement of back-action from electron spins in a gate defined GaAs double quantum dot coupled to a mesoscopic nuclear spin bath
• Calculation of tunnel-couplings in open gate-defined disordered quantum dot systems
• Feedback-tuned noise-resilient gates for encoded spin qubits
• A many-body singlet prepared by a central spin qubit
• A solvable quantum model of dynamic nuclear polarization in quantum dots
• Electron spin-flip correlations due to nuclear dynamics in driven GaAs double dots
• Third Stable Branch and Tristability of Nuclear Spin Polarization in Single Quantum Dot System
• Noise suppression and long-range exchange coupling for gallium arsenide spin qubits
• Theory on electron-phonon spin dehphasing in GaAs multi-electron double quantum dots