Octupolar Vortex Crystal and Toroidal Moment in Twisted Bilayer MnPSe3
Muhammad Akram1,2, Fan Yang3, Turan Birol3
1Department of Physics, Arizona State University, Tempe, Arizona 85287, United States.
Nano Letters
|January 27, 2025
Summary
Detecting complex antiferromagnetic order in 2D materials is difficult. This study reveals how higher-order multipole moments, specifically octupolar toroidal moments, in twisted bilayer MnPSe3 offer new ways to identify these challenging spin textures.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spintronics
Background:
- Experimental detection of antiferromagnetic order in 2D materials presents significant challenges.
- Identifying complex multidomain antiferromagnetic textures using current methods is particularly difficult.
Purpose of the Study:
- To investigate higher-order multipole moments in twisted bilayer MnPSe3.
- To explore the potential of these moments for detecting multidomain antiferromagnetic order.
Main Methods:
- Theoretical investigation of octupolar moments (M33+, M33-) in twisted bilayer MnPSe3.
- Analysis of the resultant patterns of octupole moments, forming vortex crystals.
- Identification of octupolar toroidal moments (T, Tβ).
Main Results:
- Twisted bilayer MnPSe3 exhibits a two-domain phase with significant octupolar moments M33+ and M33-.
- These octupole moments form vortex crystals, leading to octupolar toroidal moments T and Tβ.
- The identified octupolar toroidal moments can induce magnetoelectric effects and gyrotropic birefringence.
Conclusions:
- Higher-order multipole moments are crucial for identifying complex spin textures in moiré magnets.
- Octupolar toroidal moments offer indirect detection methods for multidomain antiferromagnetic order.
- This research provides novel insights into the characterization of exotic magnetic phases in 2D materials.
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