Transition-Metal-Related Quantum Emitters in Wurtzite AlN and GaN

Area of Science:

• Materials Science
• Quantum Physics
• Solid-State Chemistry

Background:

• Paramagnetic transition-metal centers in wide-bandgap semiconductors are crucial for nanophotonics and quantum information processing.
• Discovering optically controllable paramagnetic spin defects is a key research area.

Purpose of the Study:

• Investigate the electronic structure and magneto-optical properties of Cr and Mn substitutional centers in wurtzite AlN and GaN.
• Identify specific defects responsible for observed photoluminescence and assess their potential for quantum applications.

Main Methods:

• Utilized state-of-the-art hybrid density functional theory (DFT) calculations.
• Employed constrained occupation approach for excitation energies, verified with complete active space configuration interaction (CASCI).
• Calculated zero-field splitting (ZFS) parameters and simulated photoluminescence spectra.

Main Results:

• Identified Cr in AlN and Mn in GaN as responsible for narrow quantum emission near 1.2 eV.
• Determined level structure, stability, optical signatures, and magnetic properties of these centers.
• Computed ZFS parameters and proposed an optical spin polarization protocol.

Conclusions:

• Cr and Mn centers in AlN and GaN are promising candidates for spin qubits.
• These defects offer potential for optical manipulation in quantum information processing.
• The study provides a theoretical foundation for experimental realization.