Free-standing 2D non-van der Waals antiferromagnetic hexagonal FeSe semiconductor: halide-assisted chemical synthesis and Fe²⁺ related magnetic transitions

• Main Authors: Xu, Junjie, Li, Wei, Zhang, Biao, Zha, Liang, Hao, Wei, Hu, Shixin, Yang, Jinbo, Li, ShuZhou, Gao, Song, Hou, Yanglong
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; 2D-Hexagonal; Anisotropic Growth
• Online Access: https://hdl.handle.net/10356/163255
• Institution: Nanyang Technological University

The scarcity of two-dimensional (2D) magnetic nanostructures has hindered their applications in spintronics, which is attributed to that most magnetic materials exhibit non-van der Waals (nvdWs) structures and it is hard to reduce their thickness to 2D nanostructures. Thus it is necessary to develop a promising strategy for free-standing 2D magnetic nvdWs nanostructures. We have achieved free-standing 2D nvdWs hexagonal FeSe with a thickness of 2.9 nm by the reaction between the oleylamine-Se complex and Fe2+ with the assistance of Cl-, where the synergetic effects of Cl- and -NH2 lead to anisotropic growth. Inspiringly, the 2D hexagonal FeSe exhibits intrinsic antiferromagnetic order rooted in Fe2+ and semiconducting nature. In addition, the temperature variation would result in the chemical environment changes of Fe2+, responsible for the temperature-dependent magnetic transitions. This work promotes the potential applications of 2D hexagonal FeSe and the preparation of other 2D nvdWs materials.