Probing quasi-long-range ordering by magnetostriction in monolayer CoPS3

TL;DR

This study uses magnetostriction to detect quasi-long-range antiferromagnetic order in monolayer CoPS3, confirming 2D magnetic behavior and measuring interlayer interactions, advancing 2D spintronics research.

Contribution

It introduces magnetostriction as an effective method to observe quasi-long-range order in monolayer 2D magnets, specifically in CoPS3, and quantifies interlayer coupling.

Findings

Detection of phonon mode splitting below TKT indicating quasi-long-range order.

Evaluation of interlayer to intralayer interaction ratio (J'/J) as ~0.03.

Confirmation of 2D magnetic behavior in monolayer CoPS3.

Abstract

Mermin-Wagner-Coleman theorem predicts no long-range magnetic order at finite temperature in the two-dimensional (2D) isotropic systems, but a quasi-long-range order with a divergent correlation length at the Kosterlitz-Thouless (KT) transition for planar magnets. As a representative of two-dimensional planar antiferromagnets, single-layer CoPS3 carries the promise of monolayer antiferromagnetic platforms for the ultimately thin spintronics. Here, with the aid of magnetostriction which is sensitive to the local magnetic order, we observe the signatured phonon mode splitting of below TKT in monolayer CoPS3, revealing the presence of quasi-long-range ordering in XY-type antiferromagnet. Moreover, the ratio (J'/J) between the interlayer and intralayer interactions, which characterizes the 2D behaviors, is evaluated to be around 0.03 for the first time. Our results provide an efficient method to detect the quasi-long-range antiferromagnetic ordering in the two-dimensional magnets down to monolayer limit.