Perpendicular Néel Vector Detection of Monolayer Collinear Antiferromagnets with Spin-Layer Coupling

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Precise detection of perpendicular Néel vectors is crucial for advancing two-dimensional (2D) antiferromagnetic (AFM) spintronics.
• Existing methods face challenges in detecting AFM order at the nanoscale.

Purpose of the Study:

• To propose and demonstrate a method for detecting perpendicular Néel vectors in collinear AFM materials down to the monolayer limit.
• To identify suitable materials for this detection mechanism.

Main Methods:

• Theoretical proposal of using the layer Hall effect for Néel vector detection.
• Materials screening to identify candidate AFM monolayers with necessary properties (spin-layer coupling, perpendicular magnetic anisotropy).
• First-principles calculations to investigate electronic band structures and Berry curvatures.
• Experimental validation in monolayer Co₂S₂ and altermagnetic monolayer Ca(CoN)₂.

Main Results:

• Monolayer Co₂S₂ identified as a prototypical material exhibiting spin-layer coupling and perpendicular magnetic anisotropy.
• A sizable layer-polarized anomalous Hall conductivity (σxy) up to ~110 S/cm achieved in monolayer Co₂S₂.
• The sign of σxy was observed to change with the reversal of the Néel vector, enabling AFM order detection.
• Successful demonstration of Néel vector detection via the layer Hall effect in altermagnetic monolayer Ca(CoN)₂.

Conclusions:

• The layer Hall effect provides an efficient route for detecting perpendicular Néel vectors in collinear AFM materials at the monolayer limit.
• This work opens new avenues for exploring Néel vector detection in atomic-scale AFM materials and developing novel spintronic devices.