Half-Unit-Cell 伪-Fe2O3 Semiconductor Nanosheets with Intrinsic and Robust Ferromagnetism
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- 作者：Weiren Cheng ; Jingfu He ; Tao Yao ; Zhihu Sun ; Yong Jiang ; Qinghua Liu ; Shan Jiang ; Fengchun Hu ; Zhi Xie ; Bo He ; Wensheng Yan ; Shiqiang Wei
- 刊名：Journal of the American Chemical Society
- 出版年：2014
- 出版时间：July 23, 2014
- 年：2014
- 卷：136
- 期：29
- 页码：10393-10398
- 全文大小：402K
- ISSN：1520-5126
文摘
The synthesis of atomically thin transition-metal oxide nanosheets as a conceptually new class of materials is significant for the development of next-generation electronic and magnetic nanodevices but remains a fundamental chemical and physical challenge. Here, based on a 鈥渢emplate-assisted oriented growth鈥?strategy, we successfully synthesized half-unit-cell nanosheets of a typical transition-metal oxide 伪-Fe2O3 that show robust intrinsic ferromagnetism of 0.6 渭B/atom at 100 K and remain ferromagnetic at room temperature. A unique surface structure distortion, as revealed by X-ray absorption spectroscopy, produces nonidentical Fe ion environments and induces distance fluctuation of Fe ion chains. First-principles calculations reveal that the efficient breaking of the quantum degeneracy of Fe 3d energy states activates ferromagnetic exchange interaction in these Fe5-co鈥揙鈥揊e6-co ion chains. These results provide a solid design principle for tailoring the spin-exchange interactions and offer promise for future semiconductor spintronics.