Spin-State-Selective Excitation in Spin Defects of Hexagonal Boron Nitride

Area of Science:

• Materials Science
• Quantum Physics
• Nanotechnology

Background:

• Hexagonal boron nitride (hBN) is a 2D material with optically addressable spin defects.
• The negatively charged boron vacancy (V_B^-) is a key defect for quantum sensing in hBN.
• Large hyperfine interactions cause spectral overlap, limiting magnetic sensitivity.

Purpose of the Study:

• To demonstrate spin-selective excitation of V_B^- spin defects in hBN.
• To improve magnetic sensitivity and spin state control in hBN quantum sensors.

Main Methods:

• Generated circularly polarized microwaves using a cross-shaped waveguide and phase-shifted orthogonal linear polarizations.
• Utilized FPGA for precise microwave phase control.
• Employed optically detected magnetic resonance (ODMR) for experimental verification.
• Performed computational modeling to support experimental findings.

Main Results:

• Achieved spin-selective excitation of V_B^- defects (|0⟩ → |-1⟩ or |0⟩ → |1⟩).
• Confirmed selectivity through ODMR experiments and computational simulations.
• Investigated the impact of magnetic fields on spin-state selectivity.

Conclusions:

• Developed a technique for enhanced spin state control in hBN quantum defects.
• The method improves magnetic sensitivity, particularly at low and zero magnetic fields.
• This work advances hBN as a platform for high-performance quantum sensing.