title: Half-unit-cell α-Fe2O3 semiconductor nanosheets with intrinsic and robust ferromagnetism.
abstract: 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 "template-assisted oriented growth" strategy, we successfully synthesized half-unit-cell nanosheets of a typical transition-metal oxide α-Fe2O3 that show robust intrinsic ferromagnetism of 0.6 μB/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 Fe(5-co)-O-Fe(6-co) ion chains. These results provide a solid design principle for tailoring the spin-exchange interactions and offer promise for future semiconductor spintronics.
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei 230029, Anhui, People's Republic of China.
authors.forename: Weiren
authors.initials: W
authors.lastname: Cheng
authors.forename: Jingfu
authors.initials: J
authors.lastname: He
authors.forename: Tao
authors.initials: T
authors.lastname: Yao
authors.forename: Zhihu
authors.initials: Z
authors.lastname: Sun
authors.forename: Yong
authors.initials: Y
authors.lastname: Jiang
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Liu
authors.forename: Shan
authors.initials: S
authors.lastname: Jiang
authors.forename: Fengchun
authors.initials: F
authors.lastname: Hu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Xie
authors.forename: Bo
authors.initials: B
authors.lastname: He
authors.forename: Wensheng
authors.initials: W
authors.lastname: Yan
authors.forename: Shiqiang
authors.initials: S
authors.lastname: Wei