Disorder Effects in Quantum Materials

Abstract

Decades of dedicated efforts in controlling disorder in conventional semiconductors have laid the foundation for our modern civilization, based on chips and all kinds of electronic devices. Nowadays, there is a growing interest in the so-called quantum materials whose properties are fundamentally altered by quantum-mechanical effects. Such quantum materials include two-dimensional heterostructures, topological insulators, graphene, superconductors, and many others. The strong interaction between electrons and topology within quantum materials gives rise to rich quantum states and phases such as quantum Hall effects and topological phases. For example, an exciting future application of quantum materials is the topological quantum computer, which is believed to be the most robust way to process quantum information. However, engineering such quantum materials must deal with ubiquitous impurities, which often ruin the delicate quantum-mechanical effects of interest and prevent the topological quantum computation from being realized. My dissertation research focuses on analyzing how the disorder affects the resistivity of different kinds of quantum materials, e.g., topological insulator thin films and wires, non-Hermitian random lasers and photonic lattices, and GaAs/AlGaAs heterostructures. Therefore, my dissertation research on improving the understanding of disorder effects in quantum materials has a broader impact on various fields from fundamental research to material engineering and technology.