Christian Pauly demonstrates the strong topological properties of the technologically relevant phase change materials Sb2Te3 and Ge2Sb2Te5 by using two powerful techniques for mapping the surface electronic structure: scanning tunneling spectroscopy (STS) and angle-resolved photoemission spectroscopy (ARPES). In the case of a phase change material, this opens up the possibility of switching between an insulating amorphous and a conducting topological phase on nanosecond-time scales. Moreover, the author presents first experimental results of a weak topological insulator, namely on the bismuth-based graphene-like sheet system Bi14Rh3I9, revealing a topologically protected one-dimensional edge channel as its fingerprint. The edge state is as narrow as 0.8 nm, making it extremely attractive to device physics. Those strong and weak topological insulators are a new phase of quantum matter giving rise to robust boundary states which are protected from backscattering and localization.

Contents

• Fundamentals of topological insulators
• Experimental methods
• Identification of tellurium based phase change materials as strong topological insulators
• Weak topological insulators

Target Groups

• Researchers and students from the fields of physics, especially condensed materials

About the Author

Christian Pauly is working as a postdoc in the II. Institute of physics B of the RWTH Aachen University. His work focuses on the study of the topological properties of graphene-like sheet systems which belong to the class of weak topological insulators.

Autorentext

Christian Pauly is working as a postdoc in the II. Institute of physics B of the RWTH Aachen University. His work focuses on the study of the topological properties of graphene-like sheet systems which belong to the class of weak topological insulators.

Inhalt
Introduction.- Fundamentals of Topological Insulators.- Experimental Methods.- Identication of Tellurium based Phase-Change Materials as Strong Topological Insulators.- Weak Topological Insulator.- Summary.