Recent Advances in 2D Material Theory, Synthesis, Properties, and Applications

Abstract

Two-dimensional (2D) material research is rapidly evolving to broaden the spectrum of emergent 2D systems. Here, we review recent advances in the theory, synthesis, characterization, device, and quantum physics of 2D materials and their heterostructures. First, we shed insight into modeling of defects and intercalants, focusing on their formation pathways and strategic functionalities. We also review machine learning for synthesis and sensing applications of 2D materials. In addition, we highlight important development in the synthesis, processing, and characterization of various 2D materials (e.g., MXnenes, magnetic compounds, epitaxial layers, low-symmetry crystals, etc.) and discuss oxidation and strain gradient engineering in 2D materials. Next, we discuss the optical and phonon properties of 2D materials controlled by material inhomogeneity and give examples of multidimensional imaging and biosensing equipped with machine learning analysis based on 2D platforms. We then provide updates on mix-dimensional heterostructures using 2D building blocks for next-generation logic/memory devices and the quantum anomalous Hall devices of high-quality magnetic topological insulators, followed by advances in small twist-angle homojunctions and their exciting quantum transport. Finally, we provide the perspectives and future work on several topics mentioned in this review.

Observation of the Superstructure in Fe5–xGeTe2 by X-ray Fluorescence Holography

“…Two-dimensional (2D) van der Waals (vdW) materials have been widely utilized to explore unique phenomena in the 2D limit. − In the past few years, various bulk vdW ferromagnets have been discovered, including Cr­(Si,Ge)­Te 3 , − Cr­(Br,I) 3 , ,− Fe n GeTe 2 (3 ≤ n ≤ 5), − and Fe 2 Ge 2 Te 2 . In these vdW ferromagnets, the magnetic interaction is mainly generated within the 2D plane, while it is weak between layers.…”

Probing charge traps at the 2D semiconductor/dielectric interface

“…These materials offer the possibility of atomically-thin channels, efficient gate control, and emergent degrees of freedom like the valley index, interlayer twist or layer number, which are of great interest for novel memory or logic devices. 5,8–15 While early studies were focused on the intriguing properties of 2D semiconductors, more attention is now drawn towards the integration of these materials into modern electronic device architectures with state-of-the-art dielectrics. 16–19 A comprehensive approach to understand the performance of 2D semiconductor devices relies on a thorough evaluation of the material quality as well as the 2D semiconductor/dielectric interface.…”

Self-Modulated Magnetism in Two-Dimensional Ferromagnet Fe3GeTe2 Induced by Ambient Effects

“…Two-dimensional (2D) magnets with intrinsic ferromagnetism (FM) or antiferromagnetism (AFM) have attracted increasing attention, which provide an ideal platform to explore exotic 2D magnetism , and design functional 2D electronic devices to promote next-generation information technology. , Compared with conventional magnetic materials, 2D magnets have weak van der Waals (vdW) force between interlayers instead of covalent bonds and thus can be conveniently used to fabricate various functionalized heterostructures for modulating their magnetic properties, , exploring novel physical phenomena, − and designing ultrathin devices related with electronics, optoelectronics, and so on. , …”