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

• Applicant: Dr. Andrea Severing
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 324108392

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.

• DFG Programme: Research Grants
• Co-Investigators: Dr. Deepa Kasinathan; Professor Dr. Liu Hao Tjeng