LaAlO₃/SrMnO₃(111)超晶格中的界面电荷重构

Interface Electronic Reconstruction in LaAlO₃/SrMnO₃(111) Superlattices

利用第一性原理计算,在LaAlO3/SrMnO3(111)超晶格中实现了由极化电场驱动的电荷转移和半金属性。在(LaO3)/Mn界面处,电子从LaAlO3侧转移到SrMnO33中,占据Mn的eg轨道,从而形成该类超晶格中的半金属铁磁性。而在(SrO3)/La界面处,极化电场使得空穴基本上是均匀分布于SrO3面和LaO3面的氧离子上,于是造成SrMnO3中的G类反铁磁序。不过由于空穴的掺入,此类超晶格是金属性的。

Based on extensive first-principle density functional calculations, we have revealed the charge transfer and half-metallic ferromagnetism induced by the polar electronic field in LaAlO3/SrMnO3 (111) superlattices. At the (LaO3)/Mn interface, electrons transfer from LaAlO33 side to SrMnO3 component and occupy eg orbital of Mn ions, inducing half-metallic ferromagnetism of this kind of superlattice. On the other hand, for the superlattices with (SrO3)/La interface, the holes reside almost uniformly at the oxygen atoms of SrO3 and LaO3 atomic planes. With absence of the eg states at the Mn sites, bulk-like G-type AFM ordering were obvious. But this type superlattices are metallic because of hole transfer.