Composition‐Controllable Syntheses and Property Modulations from 2D Ferromagnetic Fe5Se8 to Metallic Fe3Se4 Nanosheets

• Published in: Advanced materials (Weinheim) Vol. 35; no. 1
• Main Authors: Huan, Yahuan, Luo, Tiantian, Han, Xiaocang, Ge, Jun, Cui, Fangfang, Zhu, Lijie, Hu, Jingyi, Zheng, Feipeng, Zhao, Xiaoxu, Wang, Lili, Wang, Jian, Zhang, Yanfeng
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 05.01.2023
• Subjects: Chemical vapor deposition; Composition; Controllability; Density functional theory; Electron spin; Ferromagnetic materials; Intercalation; Iron; iron selenide; Magnetic materials; Magnetic transitions; Materials science; Nanoelectronics; Nanosheets; Robustness; self‐intercalation; Spintronics; Transition metal compounds; transition metal dichalcogenides; Transition temperature; two‐dimensional magnetic materials
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202207276

Exploring new‐type 2D magnetic materials with high magnetic transition temperature and robust air stability has attracted wide attention for developing innovative spintronic devices. Recently, intercalation of native metal atoms into the van der Waals gaps of 2D layered transition metal dichalcogenides (TMDs) has been developed to form 2D non‐layered magnetic TMDs, while only succeeded in limited systems (e.g., Cr2S3, Cr5Te8). Herein, composition‐controllable syntheses of 2D non‐layered iron selenide nanosheets (25% Fe‐intercalated triclinic Fe5Se8 and 50% Fe‐intercalated monoclinic Fe3Se4) are firstly reported, via a robust chemical vapor deposition strategy. Specifically, the 2D Fe5Se8 exhibits intrinsic room‐temperature ferromagnetic property, which is explained by the change of electron spin states from layered 1T'‐FeSe2 to non‐layered Fe‐intercalated Fe5Se8 based on density functional theory calculations. In contrast, the ultrathin Fe3Se4 presents novel metallic features comparable with that of metallic TMDs. This work hereby sheds light on the composition‐controllable synthesis and fundamental property exploration of 2D self‐intercalation induced novel TMDs compounds, by propelling their application explorations in nanoelectronics and spintronics‐related fields. In this work, the composition‐controllable syntheses of 2D non‐layered iron selenide nanosheets (25% Fe‐intercalated triclinic Fe5Se8 and 50% Fe‐intercalated monoclinic Fe3Se4), via a robust chemical vapor deposition strategy is presented. Intriguingly, it has been revealed that the 2D Fe5Se8 exhibits intrinsic room‐temperature ferromagnetic property, and the ultrathin Fe3Se4 presents a novel metallic feature.