Correlated topological insulators: spectroscopic investigations combined with band structure calculations.

拓扑绝缘体形成了一种新的物质状态，为新的量子现象和原创的自旋电子学应用提供了新的机会。拓扑绝缘体具有绝缘体，并且由于拓扑考虑，必须是具有表面载流子的金属表面，表面载流子通过时间反转对称性保护以防止后向散射。到目前为止，只有半导体被认为具有这种行为，但最近的理论研究预测，强关联系统也可以显示出非平凡的拓扑性质，从而允许出现具有更奇异性质的表面现象。现在的挑战是发现这样的相关材料。理论表明，近藤绝缘体是显示拓扑非平凡表面态的很有前途的候选材料。这个项目的主题是找出目前已知的近藤绝缘子是否满足非平凡拓扑的条件。我们将通过用现代X射线方法研究块体来实现这一点，并将其与使用表面的拓扑性质是块体属性的概念的能带结构计算相结合。

Topological insulators form a novel state of matter providing new opportunities for novel quantum phenomena as well as original spintronics applications. Topological insulators have an insulating bulk and due to topological considerations necessarily a metallic surface with surface charge carriers that are protected against backscattering by time reversal symmetry. So far only semiconductors were considered to exhibit this behavior but recent theoretical studies predict that also strongly correlated systems can show nontrivial topological properties, thereby allowing the emergence of surface phenomena with even more exotic properties. The challenge is now to discover such correlated materials. Theory suggests that Kondo insulators are promising candidates for exhibiting topological nontrivial surface states. Subject of this project is to find out whether Kondo insulators which are known today fulfill the conditions for nontrivial topology. We will achieve this by investigating the bulk with modern x-ray methods and combine it with band structure calculations using the notion that the topological nature of the surface is a bulk property.