Talk given by Prof. Markus Morgenstern Topology is a new paradigm in solid state physics predicting robust physical properties by so-called topological indices which are related to fundamental symmetries of the Hamiltonian. Using data from low-temperature scanning tunneling microscopy, I will provide an illustrated introduction into the new approach starting with quantum Hall systems and their real space representation of transitions between topological indices. Subsequently, weak topological insulators, which are the stacked counterparts without magnetic field, thus, probably providing an efficient bulk spin filter, are investigated and their robust edge states are revealed in real space. Finally, a new 3D topological insulator (Ge2Sb2Te5) which is already in use in a multitude of applications in information technology without knowledge of its topological properties will be introduced. Above: Local density of states including the extended state of the zeroth Landau level of an InAs two dimensional electron system. Below: STM image of a zigzag step edge of the weak topological insulator Bi14Rh3I9 (top) and local density of states within the inverted band gap showing the protected edge state as marked (bottom).

This event is part of the eventgroup INT Talks

Homepage
https://www.int.kit.edu/events.php

Speaker
Prof. Markus Morgenstern

II. Institute of Physics and JARA-FIT, RWTH Aachen, D-52074 Aachen, Germany

Organizer
Dr. Igor Gornyi
Institute of Nanotechnology (INT)
Karlsruhe Institute of Technology (KIT)
Eggenstein-Leopoldshafen
Mail: igor gornyi ∂does-not-exist.kit edu

Targetgroup
Interested / Everyone