Polar Catastrophe, Orbital Reconstruction, and Emergent Ferromagnetic Exchange Coupling at the SrFeO2(001) Surface

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• 作者：Hai-Shuang Lu ; Tian-Yi Cai ; Sheng Ju ; Chang-De Gong
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 6, 2015
• 年：2015
• 卷：119
• 期：31
• 页码：17673-17679
• 全文大小：493K
• ISSN：1932-7455

文摘

The FeO₂-terminated (001) surface of the stable antiferromagnetic insulating phase of the infinite-layer oxide SrFeO₂ is found to undergo a magnetic reconstruction consisting of a spin-flip process at the surface: Each Fe spin at the surface flips to pair with one in the subsurface layer. In spite of the polar catastrophe inherent at the polar surface, the behavior is driven by a reduced intra-atomic 3d_z²鈥?s hybridization and the enhanced Hund鈥檚 coupling due to surface symmetry lowering. These results, based on density-functional theory, show a surface-driven ferromagnetic exchange coupling in transition-metal oxides and provide an effective avenue to realize unusual electronic and magnetic properties.