Spin-Orbit Coupling at the Level of a Single Electron.

Area of Science:

• Quantum physics
• Condensed matter physics
• Semiconductor spintronics

Background:

• Double quantum dots are crucial for quantum information processing.
• Understanding spin dynamics in quantum dots is essential for qubit development.
• AlGaAs/GaAs heterostructures are widely used in semiconductor devices.

Purpose of the Study:

• To differentiate between spin-conserving and spin-flip tunneling events in AlGaAs/GaAs double quantum dots.
• To quantify the contribution of spin-orbit coupling to tunneling processes.
• To assess the fidelity of measurements distinguishing tunneling types.

Main Methods:

• Utilized electron counting techniques to monitor tunneling events.
• Investigated the dependence of tunneling rates on interdot tunnel coupling.
• Analyzed spin dynamics influenced by spin-orbit coupling in GaAs.

Main Results:

• Identified distinct fast (spin-conserving) and slow (spin-flip) tunneling processes.
• Determined that up to 4% of tunneling events involve spin flips due to spin-orbit coupling.
• Achieved a measurement fidelity of 99% in distinguishing spin-flip events.

Conclusions:

• Spin-orbit coupling in GaAs significantly impacts tunneling dynamics in double quantum dots.
• The ability to resolve spin-flip events with high fidelity is critical for spintronic applications.
• These findings contribute to the fundamental understanding of spin transport in semiconductor nanostructures.