SPP 1153: Clusters at Surfaces: Electron Structure and Magnetism

实验和理论研究表明，气相中原子团簇的电学和磁学性质明显不同于相应的块体材料。团簇的技术应用需要沉积在支撑表面上或嵌入介质中。由此产生的团簇系统加上基质或环境组成了纳米级的新功能元素，这使得它们适合建造具有定制性能的新材料。定义良好的表面可以作为模型系统来研究团簇与其环境的相互作用。目前，关于这类体系的研究很少，然而，这些研究表明，沉积的团簇的电子和几何性质与自由物种的偏离，从轻微的修改到完全的改变不等。这是优先计划的起点：将迄今为止分开的表面科学和群组社区的活动捆绑在一起，研究群组的电子学和磁学。例如，通过单团簇或团簇阵列的电荷输运测量可以探索量子效应及其可能与附近表面的干扰，这是一个可能应用的有趣问题。此外，带有同步辐射的飞行时间光电子能谱能够直接和详细地探索沉积的团簇的电子结构和自旋结构。其次，质量选择团簇的化学反应性与电子特征有很强的联系。最后，有几个高级理论对解决这些主题非常有帮助。优先方案的重点是由大小和量子效应控制的团簇的电子和磁性。特别是，大颗粒的化学和催化过程、表面的光刻制备和生长过程不在方案的中心。

Experimental and theoretical investigations have shown that the electronic and magnetic properties of atomic clusters in the gas phase differ significantly from those of the respective bulk materials. Technical applications of clusters require deposition on supporting surfaces or embedding in a medium. The resulting system of clusters plus substrate or environment comprise new functional elements on the nanometer scale which makes them suitable for building new materials with tailored properties. Well-defined surfaces may serve as model systems to study the interactions of clusters with their environment. Presently, only few studies of such systems are available which, nevertheless, have demonstrated deviations of the electronic and geometrical properties of deposited clusters from those of the free species which vary from slight modification to complete change. This is the starting point of the Priority Programme: Activities of the surface science and cluster communities, separated up to now, are bundled to study electronics and magnetism of clusters. E.g., charge transport measurements through single clusters or clusters arrays can explore quantum effects and their possible interference with the nearby surface, which is an interesting issue for possible applications. Moreover, time-of-flight photoelectron spectroscopy with synchrotron radiation enables direct and detailed exploration of the electronic and spin structures of deposited clusters. Next, the chemical reactivity of mass-selected clusters is strongly connected to electronic features. Finally, there are several high-level theories which are very helpful in addressing these topics.The focus of the Priority Programme are electronic and magnetic properties of clusters that are governed by size and quantum effects. In particular, chemical, catalytic processes with large particles, lithographic preparation and growth processes on surfaces are not in the center of the programme.