Shallow implanted SiC spin qubits used for sensing an internal spin bath and external YIG spins

Area of Science:

• Quantum Information Science
• Materials Science
• Solid-State Physics

Background:

• Silicon vacancy (VSi) color centers in bulk silicon carbide (SiC) are promising electron spin qubits.
• Shallow spin qubits are crucial for quantum devices but exhibit dynamics distinct from bulk qubits.

Purpose of the Study:

• To develop a method for creating shallow VSi spin qubits.
• To characterize the coherence properties and environmental interactions of these shallow qubits.
• To demonstrate the application of shallow VSi qubits in quantum sensing.

Main Methods:

• Low-energy ion implantation through a sacrificial SiO2 layer to create shallow VSi qubits.
• Hahn echo decay, dynamical decoupling (DD), and optically pumped pulsed electron-electron double resonance (OP-PELDOR) for spin bath analysis.
• Magnetic resonance measurements to detect external magnetic fields.

Main Results:

• Successfully created shallow VSi (V2) spin qubits below the SiC surface.
• Identified dipolar coupling between shallow VSi qubits and an electronic spin bath.
• Observed increased coherence times with decreasing temperature (55 μs at 297 K to 107 μs at 28 K).
• Extended coherence time to 220 μs at 100 K using DD.
• Demonstrated external spin sensing via shifts in VSi resonance lines due to a nearby YIG film's stray magnetic field.

Conclusions:

• The developed method enables the creation of shallow VSi spin qubits with tunable coherence.
• Shallow VSi qubits are suitable for PELDOR-based quantum sensors and processors.
• These qubits can be utilized for sensitive detection of external magnetic fields.