Molecular Metal Complexes as Defined Spin Impurities for Kondo Physics

由于分子电子学被认为是未来纳米电子学的候选者，分子与金属的相互作用最近引起了越来越多的关注。在这个项目中，我们将创建和研究分子携带未配对自旋的系统。我们建议研究金属中自旋自由度和传导电子之间的两种相互作用：第一种实验致力于金属传导电子对自旋自由度的动态屏蔽，这一现象与含有磁性杂质的固态金属中已知的近藤效应密切相关。为此，我们将在单分子连接中固定自旋配位化合物(例如FeII和CoII化合物)。因此，主要的观测参数将是通过自旋分子的电流的I/V依赖关系。其次，我们将研究具有两个自旋自由度的双核化合物。在这里，可以探索更复杂的近藤物理学变种。作为进一步达到的目标(并可能超过这项拨款的两年期限)，这项研究将指导单分子水平的自旋电子学，其中电子传输可以通过两个自旋的相对取向来控制。对分子和实验的要求是微妙的，迫切需要合成化学和实验物理的密切合作。

The interaction of molecules with metals has recently attracted increasing attention due to the appearance of molecular electronics as a candidate for future nanoelectronics. In this project, we will create and investigate systems where a molecule carries an unpaired spin. We propose to investigate two types of interaction between the spin degree of freedom and the conduction electrons in the metal: The first experiment is dedicated to the dynamical screening of the spin degree of freedom by the conduction electrons of the metal, a phenomenon which is closely related to the Kondo effect known in solid state metals with magnetic impurities. For that purpose, we will immobilize spin-bearing coordination compounds (e.g. FeII and CoII compounds) in single-molecule junctions. Thereby, the main observable parameter will be the I/V dependence of a current passing through the spin-bearing molecule. Second, we will investigate binuclear compounds with two spin degrees of freedom. Here, more complicated variations of Kondo physics can be explored. As a further reaching goal (and presumably beyond the two-year period for this grant), this research will guide towards Spintronics on the single-molecule level, where the electron transport can be controlled by the relative orientation of the two spins. The requirements to the molecules and the experiment are delicate and imperatively need a close cooperation between synthetic chemistry and experimental physics.