Quantum emission from coupled spin pairs in hexagonal boron nitride.

Area of Science:

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

Background:

• Optically addressable defect qubits in wide band gap materials are promising for room-temperature quantum information processing.
• Two-dimensional (2D) hexagonal boron nitride (hBN) offers potential for scalable quantum emitter and memory preparation.
• The microscopic origin and optical properties of reported hBN defect qubits remain unclear.

Purpose of the Study:

• To elucidate the microscopic origin of quantum emitters in hBN.
• To understand the nature of optical transitions and optically detected magnetic resonance (ODMR) in hBN defect qubits.
• To connect quantum emitter properties to specific defect structures.

Main Methods:

• Utilized ab initio calculations to model defect structures in hBN.
• Investigated the relationship between optical spectra, lifetimes, and spectral stability.
• Analyzed the conditions for observing ODMR signals in potential defect qubit systems.

Main Results:

• Established a connection between quantum emitter characteristics and donor-acceptor pairs (DAPs) in hBN.
• Demonstrated that DAPs can exhibit ODMR signals for the acceptor, with an S = 1/2 ground state at non-zero magnetic fields.
• Identified hyperfine interaction as the dominant mechanism mediating ODMR signals, dependent on the donor partner.

Conclusions:

• The donor-acceptor pair model provides a framework for understanding quantum emitters in hBN.
• This model facilitates the identification and optimization of defect qubits for quantum applications.
• The findings pave the way for improved performance of hBN-based quantum technologies.