Freestanding monolayer CrOCl through chemical exfoliation†

Abstract

Magnetic two-dimensional (2D) materials are a unique class of quantum materials that can exhibit interesting magnetic phenomena, such as layer-dependent magnetism. The most significant barrier to 2D magnet discovery and study lies in our ability to exfoliate materials down to the monolayer limit. Therefore designing exfoliation methods that produce clean, monolayer sheets is crucial for the growth of 2D material research. In this work, we develop a facile chemical exfoliation method using lithium naphthalenide for obtaining 2D nanosheets of magnetic van der Waals material CrOCl. Using our optimized method, we obtain freestanding monolayers of CrOCl, with the thinnest measured height to date. We also provide magnetic characterization of bulk, intercalated intermediate, and nanosheet pellet CrOCl, showing that exfoliated nanosheets of CrOCl exhibit magnetic order. The results of this study highlight the tunability of the chemical exfoliation method, along with providing a simple method for obtaining 2D CrOCl.