Center for Artificial Low Dimensional Electronic Systems

Manipulating topological spin properties

Jan Hugo Dil

January 4(Thu), 2018

Seminar Room 3-201

Manipulating topological spin properties

Jan Hugo Dil (Ecole Polytechnique Fédérale de Lausanne (EPFL)

The classification and description of the electronic structure of materials based on topology has in recent years shifted the way of thinking in condensed matter physics. The change primarily lies in the idea that the main properties are determined by general symmetries and not by fine details, especially since these details can in turn be manipulated by conventional condensed matter approaches. This means that primarily the topology of the system matters and can be used to classify materials, for example in topologically trivial and non-trivial systems. The main promise of topologically non-trivial systems lies in their peculiar spin texture and response in magneto transport, with the ultimate possibility to create Majorana like states for topologically protected quantum bits.

In this talk I will present our experiments to explore topology and topological protection and the resulting spin properties. Besides highlighting the promises of such materials I will also point out the limitations and the traps that lure when topological thinking is taken too far. Furthermore, I will show how similar spin textures can be achieved in transition metal oxides and multiferroic semiconductors with the advantage that it is possible to manipulate the properties with conventional semiconductor technology. The techniques used range from a variety of spectroscopic techniques such as spin- and angle-resolved photoemission ((S)ARPES), soft X-ray ARPES, magnetic circular dichroism (XMCD), to real space techniques like combined STM and AFM.