Spin Hall and Edelstein effects in chiral non-collinear altermagnets

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Altermagnets are magnetic phases with ferromagnetic spin polarization and antiferromagnetic net magnetization.
• The concept of altermagnetism, initially for collinear structures, now includes non-collinear systems.
• Landau theory with spin-space symmetries aids in identifying collinear altermagnets.

Purpose of the Study:

• To extend Landau theory for collinear altermagnets to identify altermagnetic multipolar order parameters in non-collinear chiral materials.
• To explore the unique interplay between non-collinear altermagnetism and chirality.
• To predict experimental signatures of these phenomena in chiral altermagnets.

Main Methods:

• Expansion of Landau theory to incorporate non-collinear chiral altermagnets.
• Application of toy models and first-principles calculations.
• Case study using the chiral topological magnetic material Mn3IrSi.

Main Results:

• Identification of altermagnetic multipolar order parameters in non-collinear chiral materials.
• Demonstration of spatially odd multipole components due to altermagnetism-chirality interplay.
• Prediction of non-trivial Fermi surface spin textures and novel transport phenomena (e.g., large spin Hall and Edelstein effects) even without spin-orbit coupling (SOC).

Conclusions:

• Chiral altermagnets offer fundamentally different spintronic properties compared to SOC-driven effects.
• Predicted large spin Hall and Edelstein effects in Mn3IrSi, unobserved in altermagnets previously.
• Findings open new avenues for spintronics applications utilizing chiral altermagnet properties.