Interface structure and magnetism of Fe3Si/GaAs(110) multilayers: An ab-initio study
Interface structure and magnetism of Fe3Si/GaAs(110) multilayers: An ab-initio study
复制标题
DOI：
10.1080/14786430802277657
复制
发表时间：
2008-06
影响因子：
1.6
通讯作者：
H. Herper;P. Entel
中科院分区：
文献类型：
--
作者：
H. Herper;P. Entel
铁磁-半导体（FM/SC）混合结构由于材料适合于自旋电子器件而引起了人们的极大兴趣。这种器件需要在FM/SC界面处的高自旋极化，如由Fe3Si提供的。在这里，我们调查的混合系统组成的Fe3Si和GaAs是特别感兴趣的，由于其微小的晶格失配。多层膜中含有1 - 3层厚的Fe_3Si薄膜，薄膜取向为（110）方向。使用GaAs的（110）取向具有不必考虑表面重构的优点。自由GaAs（110）表面只显示出一个波纹，但没有重构。利用密度泛函理论研究了GaAs（110）衬底上Fe3Si薄膜的结构和磁性。因此，我们选择多层几何结构，以避免来自表面的额外贡献。结果表明，基态结构是相同的，与FM层的数量无关，并且如果被Fe3Si过度生长，则波纹状GaAs（110）表面被平坦化。此外，我们发现该系统是稳定的扩散效应，导致平均磁矩的数量级的散装Fe3Si。关于磁矩的大小，我们的计算表明，Fe_3Si/GaAs（110）可能是一个很好的候选磁电子学。
Ferromagnet-semiconductor (FM/SC) hybrid structures have attracted much interest in view of materials being suitable for spintronic devices. Such devices demand a high spin-polarization at the FM/SC interface, as is provided by Fe3Si. Here, we investigate the hybrid system consisting of Fe3Si and GaAs which is of special interest due to its tiny lattice mismatch. The multilayers containing 1–3 layer thick Fe3Si films are oriented in the (110) direction. Using the (110) orientation of GaAs has the advantage that no surface reconstruction has to be considered. Free GaAs(110) surfaces show only a rippling but no reconstruction. We investigate the structural and magnetic properties of thin layers of Fe3Si on GaAs(110) using density functional theory. Therefore we choose a multilayer geometry in order to avoid additional contributions from the surface. The ground state structure turns out to be the same, independently of the number of FM layers, and the rippled GaAs(110) surface is flattened if overgrown by Fe3Si. Moreover, we find the system being stable against diffusion effects which leads to average magnetic moments of the magnitude of bulk Fe3Si. Concerning the magnitude of the magnetic moments, our calculations suggest that Fe3Si/GaAs(110) may be a good candidate for magnetoelectronics.