Néel spin-orbit torque in antiferromagnetic quantum spin and anomalous Hall insulators

Area of Science:

• Condensed Matter Physics
• Spintronics
• Materials Science

Background:

• The interplay between topological electrons and magnetic ordering is key for electrical control of magnetism.
• Existing methods for electrical control of magnetism often require net magnetization or suffer from energy losses.

Purpose of the Study:

• To extend the Kane-Mele model to incorporate antiferromagnetic (AFM) order and investigate novel topological phenomena.
• To realize and characterize a Néel-type spin-orbit torque (NSOT) driven by electric fields in AFM systems.

Main Methods:

• Theoretical extension of the Kane-Mele model to include exchange coupling with collinear AFM order.
• Analysis of topological phases, including the quantum anomalous Hall and quantum spin Hall effects.
• Investigation of the staggered Edelstein effect for generating spin polarization in AFM sublattices.

Main Results:

• The extended model predicts quantum anomalous Hall and quantum spin Hall effects without net magnetization.
• A novel NSOT is realized through a bulk, adiabatic effect driven by an applied electric field.
• This NSOT efficiently drives antiferromagnetic resonance with microwave electric fields, significantly outperforming magnetic field excitation.

Conclusions:

• The study establishes a new mechanism for electrical control of antiferromagnetism via NSOT.
• This adiabatic, bulk NSOT offers a pathway for highly efficient, low-loss spintronic devices.
• The findings open avenues for novel microwave-driven antiferromagnetic technologies.