Controlled Synthesis of a Two-Dimensional Non-van der Waals Ferromagnet toward a Magnetic Moiré Superlattice

Abstract

Two-dimensional (2D) magnetic materials provide an ideal platform for spintronics, magnetoelectrics, and numerous intriguing physical phenomena in 2D limits. Moireś uperlattices based on 2D magnets offer an avenue for controlling the spin degree of freedom and engineering magnetic properties. However, the synthesis of high-quality, large-grain, and stable 2D magnets, much less obtaining a magnetic moirésuperlattice, is still challenging. We synthesize 2D ferromagnets (trigonal Cr 5 Te 8 ) with controlled thickness and robust stability through chemical vapor deposition. Singleunit-cell-thick flakes with lateral sizes of tens of micrometers are obtained. We observe the layer-by-layer growth mode for the crystal formation in non-van der Waals Cr 5 Te 8 . The robust anomalous Hall signal confirms that Cr 5 Te 8 of varying thickness have a long-range ferromagnetic order with an out-of-plane easy axis. There is no obvious change of the Curie temperature when the thickness of Cr 5 Te 8 decreases from 52.1 to 7.2 nm. Here, we construct diverse 2D non-van der Waals/van der Waals vertical heterostructures (Cr 5 Te 8 /graphene, Cr 5 Te 8 /h-BN, Cr 5 Te 8 /MoS 2 ). A uniform moirésuperlattice is formed in the heterostructure through a lattice mismatch. The successful growth of 2D Cr 5 Te 8 and a related moirésuperlattice introduces 2D non-van der Waals ferromagnets into moirésuperlattice research, thus highlighting prospects for property investigation of a non-van der Waals magnetic moirésuperlattice and massive applications which require a scalable approach to magnetic moirésuperlattices.

Large antiferromagnetic fluctuation enhancement of the thermopower at a critical doping in magnetic semimetal Cr1+δTe2

“…Among the magnetic TMDs, Cr 1+δ Te 2 [Fig. 1(a)] is a promising selfintercalated ferromagnet with widely tunable electronic and magnetic properties [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Our recent efforts have yielded a unique recipe for the growth of epitaxial thin films of Cr 1+δ Te 2 over a wide compositional range [37].…”

Non‐van der Waals 2D Materials for Electrochemical Energy Storage

“…[9e,63] With this technique, the synthesis of high-quality 2D nvdW Cr 5 Te 8 with tunable thickness has been achieved. [64] A thin and c) HR-TEM of the exfoliated Na-Bir-5. Reproduced with permission.…”

“…With this technique, the synthesis of high‐quality 2D nvdW Cr 5 Te 8 with tunable thickness has been achieved. [ 64 ] A thin Cr 5 Te 8 flake of a single unit cell thickness and lateral size of tens of micrometers was obtained, showing metallic or ferromagnetic properties depending on the growth time which affected the thickness. The Cr 5 Te 8 flakes were stable during aging and deterioration testing which could be connected to the continuous layer structure instead of discrete islands (multidomain 2D crystals).…”

Electronic properties of twisted multilayer graphene

“…These explorations have also inspired researchers to extendedly apply the twist approach to other physical systems, e.g. magnetic 2D materials [44][45][46][47][48] and photonic layered structures [49][50][51][52]. In overall, the properties of those systems are definitely dependent of their constituting layers and importantly, can be tuned by varying their twist angle, similar to those observed in TBLG.…”