Magnetic Characterization and Synthesis Optimization of Layered CrX2 (X = Se, Te) and its Variants from Bulk KCrX2 Crystals

Abstract

There has been a recent surge of research efforts in understanding and finding two-dimensional materials with magnetic properties which are expected to serve as the foundation of several applications in the information, electronic, and energy fields. One such family of these materials is called transition metal dichalcogenides (TMDs) where crystal layers are normally bound by weak van der Waals forces and are mechanically exfoliated with scotch tape. However, promising TMDs such as CrX2 (X = Se, Te) must first be deintercalated from KCrX2 which renders traditional means of exfoliation ineffective. The deintercalation treatment likely results in defective structures, which has not yet been investigated carefully. Furthermore, mechanical exfoliation does not produce a high yield of sheets which limits the ability for these materials to be commercialized. An alternative method called chemical exfoliation has been proposed to create uniform few and monolayer sheets of CrX2. However, synthesis methods and subsequent quality of results vary in the literature. As a result, recent papers claiming to have produced few and monolayered sheets of CrX2 have data and synthesis methods that are more consistent with compound analogues, such as Cr2Se3. In my research, I present the optimal synthesis methods of these layered materials and demonstrate with what methods analogues are formed. Characterization of the lattice parameters, chromium position, and magnetic measurements are also reported, comparing results to the current literature.