Floquet Spin Splitting and Spin Generation in Antiferromagnets

Area of Science:

• Spintronics
• Condensed Matter Physics
• Quantum Optics

Background:

• Antiferromagnetic spintronics requires manipulating spin degrees of freedom, typically by lifting spin degeneracy.
• Current methods rely on spin-orbit coupling or altermagnet spin splitting.
• Controlling spins is key for generating spin currents and magnetic order.

Purpose of the Study:

• To propose and demonstrate a new method for inducing dynamical spin splitting in antiferromagnets using optical fields.
• To explore the generation of spin currents and spin accumulation without spin-orbit coupling.
• To provide a tunable route for spin control in antiferromagnetic materials.

Main Methods:

• Applying an optical field to induce dynamical spin splitting in antiferromagnets.
• Coupling the driven system to a thermal bath.
• Analyzing the emergence of steady-state and linear-response spin currents.

Main Results:

• Demonstrated the emergence of steady-state pure spin currents.
• Observed linear-response longitudinal and transverse spin currents.
• Achieved a nonrelativistic Edelstein effect (net spin accumulation) via thermal bath engineering, bypassing spin-orbit coupling.

Conclusions:

• Dynamical spin splitting induced by optical fields offers a new pathway for spin control in antiferromagnets.
• Thermal bath engineering enables nonrelativistic spin generation, broadening applications in spintronics.
• This approach provides a broadly applicable and tunable method for antiferromagnetic spintronics.