Ising-Type Magnetic Ordering in Atomically Thin FePS₃

TLDR

Magnetism in two-dimensional materials is of fundamental interest and promising for applications, yet experimental studies have mainly focused on extrinsic effects such as defects, vacancies, edges, or dopants. Here, we report on the observation of intrinsic antiferromagnetic ordering in the two-dimensional limit. By monitoring Raman peaks arising from zone folding due to antiferromagnetic ordering at the transition temperature, we demonstrate that FePS₃ exhibits an Ising‑type antiferromagnetic ordering down to the monolayer limit, in good agreement with the Onsager solution for two‑dimensional order–disorder transition. The transition temperature remains almost independent of thickness from bulk to monolayer, with T_N ∼ 118 K, indicating that weak interlayer interactions have little effect on the antiferromagnetic ordering.

Abstract

Magnetism in two-dimensional materials is not only of fundamental scientific interest but also a promising candidate for numerous applications. However, studies so far, especially the experimental ones, have been mostly limited to the magnetism arising from defects, vacancies, edges, or chemical dopants which are all extrinsic effects. Here, we report on the observation of intrinsic antiferromagnetic ordering in the two-dimensional limit. By monitoring the Raman peaks that arise from zone folding due to antiferromagnetic ordering at the transition temperature, we demonstrate that FePS3 exhibits an Ising-type antiferromagnetic ordering down to the monolayer limit, in good agreement with the Onsager solution for two-dimensional order–disorder transition. The transition temperature remains almost independent of the thickness from bulk to the monolayer limit with TN ∼ 118 K, indicating that the weak interlayer interaction has little effect on the antiferromagnetic ordering.