Strong and Weak Topology Probed by Surface Science [electronic resource] : Topological Insulator Properties of Phase Change Alloys and Heavy Metal Graphene /
Pauly, Christian.author.
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.
Description based upon print version of record.
Acknowledgments; Contents; 1 Introduction; 2 Fundamentals of Topological Insulators; 2.1 Introduction; 2.2 Insulators with metallic boundary states ; 2.2.1 Integer quantum Hall effect; 2.2.2 The Hall conductance as a topological invariant; 2.2.3 Quantum spin Hall effect or time-reversal invariant 2D topological insulator; 2.2.4 Construction of Z2 invariant for 2D topological insulators ; 2.2.5 Generalization to three-dimensions; 2.2.6 Weak topological insulators; 2.2.7 Experimental realizations of 3D topological insulators; 3 Experimental Methods ; 3.1 Scanning tunneling microscopy
3.1.1 Tersoff-Hamann model 3.1.2 Scanning tunneling spectroscopy; 3.1.3 STM and STS experiments ; 3.2 Angle-resolved photoemission spectroscopy; 3.2.1 Spin-resolved ARPES; 3.2.2 Experimental details: ARPES at the synchrotron; 4 Identification of Tellurium based Phase-Change Materials as Strong Topological Insulators; 4.1 Fundamentals of phase-change materials; 4.2 Identification of topological insulator properties in crystalline Sb2Te3; 4.2.1 STM and STS characterization of Sb2Te3; 4.2.2 Spin-resolved ARPES measurements of Sb2Te3
4.3 Characterization of crystalline Ge2Sb2Te5 in terms of topological insulator4.3.1 Stacking order of Ge2Sb2Te5 in the crystalline phase; 4.3.2 Preparation and characterization of metastable crystalline Ge2Sb2Te5 samples; 4.3.3 Evidence for topological band inversion in metastable crystalline Ge2Sb2Te5 measured by ARPES; 5 Weak Topological Insulator ; 5.1 General description of the first synthesized weak topological insulator Bi14Rh3I9; 5.2 Edge states at the dark side of the weak topological insulator Bi14Rh3I9 probed by STS
5.2.1 Identification of the atomic and electronic structure of the different layers in Bi14Rh3I9 by STM5.2.2 Bias-dependent structural variations of the morphology of the 2D TI and spacer layer in Bi14Rh3I9; 5.2.3 Probing the edge state at the step edge of the 2D TI layer in Bi14Rh3I9; 5.2.4 Evidence for the topological nature of the edge state in Bi14Rh3I9; 5.2.5 Absence of an edge state in the structural closely related but topologically trivial material Bi13Pt3I7; 5.2.6 Computational details; 6 Summary; Bibliography; Publications; Publications described within this thesis
Further publications
Includes bibliographical references.
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.
Solid state physics.
Nanoscale science.
Nanoscience.
Nanostructures.
Spectroscopy.
Microscopy.
Solid State Physics.
Nanoscale Science and Technology.
Spectroscopy and Microscopy.