Orbital Reconstruction and Interface Ferromagnetism in Self-Assembled Nanosheet Superlattices

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• 作者：Minoru Osada ; Takayoshi Sasaki ; Kanta Ono ; Yoshinori Kotani ; Shigenori Ueda ; Keisuke Kobayashi
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：September 27, 2011
• 年：2011
• 卷：5
• 期：9
• 页码：6871-6879
• 全文大小：1072K
• 年卷期：0
• ISSN：1936-086X

文摘

We have investigated the interface electronic states in self-assembled (Ti_0.8Co_0.2O₂/Ti_0.6Fe_0.4O₂)_n superlattices by X-ray photoelectron spectroscopy. A charge of about −0.3 electron is transferred from Fe to Co ions across the interface and induces a major reconstruction of the orbital occupation at the interfacial (Ti_0.8Co_0.2O₂/Ti_0.6Fe_0.4O₂) layers. Supported by first-principles calculations, the Co³⁺ state is partially occupied at the interface by superlattice formation, and this new magnetic state directly influences the coupling between Ti_0.8Co_0.2O₂ and Ti_0.6Fe_0.4O₂ nanosheets. These data indicate that the orbital reconstruction is indeed realized by the interface charge transfer between Co and Fe ions in the adjoined nanosheets, and the generic feature of engineered interfaces can be extended to self-assembled superlattices of oxide nanosheets.