Molecular Beam Epitaxy Synthesis and Nanoscale Characterization of Topological Insulator Thin Films and Their Interface With High-temperature Superconductors

Abstract

The discovery of topological phases has ushered in an era of new materials with exotic electronicproperties; one particular area of excitement is realizing and studying topologically superconducting systems. These topological superconductors are theorized to host exotic excitations that can be applied towards making fault tolerant quantum computations. One way to achieve this is depositing thin films of topological insulators onto superconducting substrates. Molecular beam epitaxy offers precise control for fabricating thin film heterostructures down to the single layer limits. In this thesis I will present my work on the synthesis of thin film topological insulators grown epitaxially on both an iron based superconductor FeT e0.55Se0.45 as well as a cuprate superconductor Bi2Sr2CaCu2Ox+8. Additionally I will cover the scanning tunneling microscopy/spectroscopy characterization of the emergent phenomena on the surface as well as at the interface of these heterostructures. This work presents a viable platform for exploring the emergence of superconductivity in topologically insulating materials, as well as demonstrates the importance of a clean interface.