Multiple spin-phonon relaxation pathways in a Kramer single-ion magnet.

Area of Science:

• Condensed Matter Physics
• Quantum Magnetism
• Materials Science

Background:

• Single-ion magnets (SIMs) are crucial for quantum technologies.
• Understanding spin relaxation mechanisms is vital for SIM performance.
• Spin-phonon coupling governs relaxation pathways.

Purpose of the Study:

• To investigate spin-phonon relaxation in Co2+ SIMs.
• To elucidate the atomistic origins of Orbach and Raman relaxation channels.
• To determine the influence of molecular vibrations on magnetic relaxation.

Main Methods:

• First-principles electronic structure calculations.
• Machine-learning force fields for atomistic simulations.
• Analysis of spin-phonon interactions and energy landscapes.

Main Results:

• Identified THz-range phonons as dominant in low-temperature spin dynamics.
• Showed that excited spin states mediate both Orbach and Raman relaxation.
• Demonstrated that intra-molecular motions significantly affect relaxation mechanisms.
• Found that phonons partially counteract large magnetic anisotropy benefits.

Conclusions:

• Spin-phonon coupling critically influences Co2+ SIM relaxation.
• Intra-molecular vibrations play a key role in relaxation processes.
• Provides a pathway for designing SIMs with controlled spin-phonon interactions.