Two-Dimensional Dual-Switchable Ferroelectric Altermagnets: Altering Electrons and Magnons

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Two-dimensional (2D) materials offer unique properties for advanced electronics.
• Controlling electron spin textures and magnonic excitations separately is challenging.
• Unified electrical control over coupled electronic and magnonic properties in 2D is unexplored.

Purpose of the Study:

• Predict a new class of 2D materials, ferroelectric altermagnets (FEAMs).
• Investigate the mechanism for unified electrical control of spin and magnonic properties.
• Establish material-specific pathways for novel spintronic and magnonic devices.

Main Methods:

• Symmetry analysis
• First-principles calculations
• Database screening for candidate materials (e.g., CrPS3, V2I2O2BrCl)

Main Results:

• Identified dual-switchable ferroelectric altermagnets (FEAMs).
• Demonstrated that ferroelectric polarization reversal simultaneously alters electronic spin splitting and magnonic chirality splitting.
• Elucidated the mechanism involving specific atomic displacements breaking inversion symmetry while preserving spin group symmetries.

Conclusions:

• FEAMs enable unified electrical manipulation of electron spin textures and magnon excitations in 2D.
• Experimental observation possible via magneto-optical Kerr effect sign change.
• Paves the way for multifunctional spintronic and magnonic applications.