Electronic and magnetic properties of the interface between metal-quinoline molecules and cobalt
Electronic and magnetic properties of the interface between metal-quinoline molecules and cobalt
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DOI：
10.1103/physrevb.89.094412
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发表时间：
2014-03-12
影响因子：
3.7
通讯作者：
Cinchetti, Mirko
中科院分区：
文献类型：
--
作者：
Droghetti, Andrea;Steil, Sabine;Cinchetti, Mirko
最近的研究表明，从铁磁金属到有机半导体的自旋注入在很大程度上取决于杂化界面态的形成。在这里，我们调查是否钴和三（8-羟基喹啉）-Al（III）（Alq 3），最突出的分子候选人的organicspin-valve设备之间的界面的磁性能，可以通过用镓或铟取代铝原子进行修改。实验上，通过使用不同的光电子能谱方法，并从理论上，通过密度泛函理论计算的Alq 3，Gaq 3和Inq 3的电子结构和它们与铁磁钴的界面的性质进行了探测。对于所有的情况下，结果突出了自旋极化界面态的存在。然而，没有观察到各种分子和界面的性质之间的显着差异。这是由于分子前线轨道主要位于配体上，并且它们仅显示来自金属离子的可忽略的贡献。
It was recently established that spin injection from a ferromagnetic metal into an organic semiconductor depends largely on the formation of hybrid interface states. Here we investigate whether the magnetic properties of the interface between cobalt and tris( 8-hydroxyquinolinato)-Al( III) ( Alq3), the most prominent molecular candidate for organicspin-valve devices, can be modified by substituting the aluminum atom with either gallium or indium. The electronic structure of Alq3, Gaq3, and Inq3 and the properties of their interfaces with ferromagnetic cobalt are probed experimentally, by using different photoemission spectroscopy methods, and theoretically, through density functional theory calculations. For all cases, the results highlight the presence of spin-polarized interface states. However no striking difference between the properties of the various molecules and interfaces is observed. This is a consequence of the fact that the molecules frontier orbitals are mainly localized on the ligands and they show only a negligible contribution coming from the metal ion.