Half-Metallic Ferromagnetism via the Interface Electronic Reconstruction in LaAlO3/SrMnO3 Nanosheet Superlattices
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- 作者：Fang Hou ; Tian-Yi Cai ; Sheng Ju ; Ming-Rong Shen
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：October 23, 2012
- 年：2012
- 卷：6
- 期：10
- 页码：8552-8562
- 全文大小：989K
- 年卷期：v.6,no.10(October 23, 2012)
- ISSN：1936-086X
文摘
Spintronic devices are very important for future information technology. Suitable materials for such devices should have half-metallic properties with only one spin channel conducting. Nanostructures have played an important role in this aspect. Here, we report the realization of robust half-metallic ferromagnetism via the interface electronic reconstruction in artificial LaAlO3/SrMnO3 nanosheet supperlattices. On the basis of first-principles density-functional calculations, we reveal an obvious electron transfer from the (LaO)+ layer to the adjacent (MnO2)0 layer. And the partially occupied eg orbitals at the Mn sites can mediate a half-metallic state via a Zener double-exchange mechanism. On the other hand, for the superlattices with a (SrO)0/(AlO2)鈭?/sup> interface, hole transfer at the interface is identified. These transferred holes reside mainly at oxygen sites in SrMnO3, leading to either the preserved G-type AFM ordering in pp-type superlattices or complex magnetic ordering in np-type superlattices. Interestingly, when these systems transit to ferromagnetic ordering by an external magnetic field, an obvious change of electronic state at the Fermi level is found, suggesting a large magnetoresistive effect therein. Our studies demonstrate the unique electric and magnetic properties arising from a magnetic ordering dependent charge transfer and electronic reconstruction at perovskite heterointerfaces, and their potential applications in spintronic devices.