Electrical Read-Out of a Single Spin Using an Exchange-Coupled Quantum Dot

Area of Science:

• Quantum Computing
• Condensed Matter Physics
• Nanotechnology

Background:

• Accurate readout of single electronic spins is crucial for quantum information processing.
• Existing spin detection methods often rely on spin-to-charge conversion, which is not universally applicable.

Purpose of the Study:

• To introduce a novel, all-electrical, and nondestructive method for continuous single electronic spin readout.
• To demonstrate the effectiveness of a spin-dependent exchange interaction for spin detection.

Main Methods:

• Utilizing an exchange interaction between a single electronic spin and a nearby read-out quantum dot.
• Measuring spin-dependent conductance variations through the quantum dot.
• Employing a semiclassical approach to model the asymmetric exchange coupling.

Main Results:

• Achieved continuous, nondestructive single spin detection with high fidelity (>99.5%).
• Observed conductance variations up to 4% due to the spin-dependent exchange interaction.
• Developed an asymmetric exchange coupling model that accurately reflects experimental outcomes.

Conclusions:

• The presented detection scheme offers a viable alternative for single spin readout, particularly in systems where spin-to-charge conversion is challenging.
• This all-electrical method enhances the capabilities for quantum state manipulation and measurement.
• The validated theoretical model provides a foundation for further optimization of spin detection techniques.