Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS3

TL;DR

This study investigates how the antiferromagnetic order in NiPS3 diminishes as the material is thinned down to a monolayer, demonstrating the transition from XXZ to XY behavior and the loss of long-range magnetic order.

Contribution

It provides experimental evidence of the suppression of magnetic order in monolayer NiPS3, confirming theoretical predictions about 2D XY behavior in XXZ systems.

Findings

Magnetic order disappears in monolayer NiPS3.

Experimental data aligns with renormalization group theory.

2D NiPS3 exhibits XY-like behavior at low temperatures.

Abstract

How a certain ground state of complex physical systems emerges, especially in two-dimensional materials, is a fundamental question in condensed-matter physics. A particularly interesting case is systems belonging to the class of XY Hamiltonian where the magnetic order parameter of conventional nature is unstable in two-dimensional materials leading to a Berezinskii-Kosterlitz-Thouless transition. Here, we report how the XXZ-type antiferromagnetic order of a magnetic van der Waals material, NiPS3, behaves upon reducing the thickness and ultimately becomes unstable in the monolayer limit. Our experimental data are consistent with the findings based on renormalization group theory that at low temperatures a two-dimensional XXZ system behaves like a two-dimensional XY one, which cannot have a long-range order at finite temperatures. This work provides experimental examination of the XY magnetism in the atomically thin limit and opens new opportunities of exploiting these fundamental theorems of magnetism using magnetic van der Waals materials.