Magnetic properties of restacked 2D spin $\frac{1}{2}$ honeycomb RuCl$_3$ nanosheets

TL;DR

This study explores the exfoliation and magnetic properties of restacked RuCl₃ monolayers, revealing how turbostratic stacking influences magnetic behavior and offers insights into 2D quantum magnetic systems.

Contribution

It reports the first halide monolayers of RuCl₃ and investigates how turbostratic stacking affects their magnetic properties, providing a new platform for 2D quantum magnetism research.

Findings

Exfoliation of RuCl₃ into monolayers achieved via reductive lithiation/hydration.

Restored magnetic transition at T_N = 7 K in oxidized, restacked layers.

Out-of-plane magnetic properties differ significantly from bulk RuCl₃.

Abstract

Spin $\frac{1}{2}$ honeycomb materials have gained substantial interest due to their exotic magnetism and possible application in quantum computing. However, in all current materials out-of-plane interactions are interfering with the in-plane order, hence a true 2D magnetic honeycomb system is still of demand. Here, we report the exfoliation of the magnetic semiconductor $\alpha$-RuCl$_3$ into the first halide monolayers and the magnetic characterization of the spin $\frac{1}{2}$ honeycomb arrangement of turbostratically stacked RuCl$_3$ monolayers. The exfoliation is based on a reductive lithiation/hydration approach, which gives rise to a loss of cooperative magnetism due to the disruption of the spin $\frac{1}{2}$ state by electron injection into the layers. After an oxidative treatment, cooperative magnetism similar to the bulk is restored. The oxidized pellets of restacked single layers feature a magnetic transition at T$_N$ = 7 K in the in-plane direction, while the magnetic properties in the out-of-plane direction vastly differ from bulk $\alpha$-RuCl$_3$. The macroscopic pellets of RuCl$_3$ therefore behave like a stack of monolayers without any symmetry relation in the stacking direction. The deliberate introduction of turbostratic disorder to manipulate the spin structure of RuCl$_3$ is of interest for research in frustrated magnetism and complex magnetic order as predicted by the Kitaev-Heisenberg model.