Electric-field control of spin orientation of manganocene: An insight into molecule-substrate interactions
Electric-field control of spin orientation of manganocene: An insight into molecule-substrate interactions
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电场控制二茂锰自旋方向：深入了解分子-基底相互作用
DOI：
10.1063/1.5064687
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发表时间：
2019
影响因子：
4.4
通讯作者：
Zhang Yachao
中科院分区：
文献类型：
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作者：
Zhang Yachao
组装在表面上的分子纳米磁体的自旋取向的操纵对于存储器件的发展是必不可少的。这些性质主要由与基材的相互作用决定。在这里，我们表明，个别manganocene分子沉积在Cu（111）表现出不同的易磁化方向，在施加的电场，由于不同的接触几何形状。采用Hubbard-U修正的密度泛函理论描述强关联效应，采用非自洽对角化方法处理自旋轨道耦合，证明了场诱导自旋重取向跃迁发生在直立分子的高自旋态和低自旋态，而对于平躺分子，场诱导自旋重取向跃迁只发生在高自旋态.我们提出了合理的机制，在界面处的电荷极化以及费米能级EF附近的电子态的修改。我们表明，分子在很大程度上保留其排列的3d轨道在站立的配置由于“绝缘层”（桥接配体），而直接接触的Mn离子与衬底在说谎的配置诱导EF周围的轨道简并，从而防止磁各向异性的电调制。
The manipulation of spin orientations in molecular nanomagnets assembled on surfaces is essential for the development of memory devices. These properties are dominated by interactions with the substrate. Here, we show that individual manganocene molecules deposited on Cu(111) exhibit different easy magnetization directions in an applied electric-field due to different contact geometries. Using Hubbard-U corrected density-functional theory to describe strong correlation effects and a non-self-consistent diagonalization method to treat spin-orbit coupling, we demonstrate that the field-induced spin reorientation transition occurs in the standing-up molecule in both high-spin (HS) and low-spin states, while the transition only occurs in the HS state for the flat-lying molecule. We propose plausible mechanisms in terms of charge polarization at the interface as well as modifications of the electronic states near the Fermi level EF. We show that the molecule largely preserves its arrangement of 3d orbitals in the standing configuration due to the “insulating layer” (bridging ligand), whereas direct contact of the Mn ion with the substrate in the lying configuration induces an orbital degeneracy around EF, thus preventing the electrical modulation of magnetic anisotropies.