Grant: Discovery Grants Program - Individual

Quantum materials are solids in which quantum mechanics, normally associated with the atomic and subatomic scales, directly manifests in their macroscopic scale observable properties. Such "macroscopic quantum phenomena" are not just interesting fundamentally but are also of great practical importance. It is certain we will be using quantum mechanics in much more creative ways than we are now in future technologies, and the ongoing fundamental study of quantum materials is currently laying the foundation for the coming quantum technology revolution.   Topological Semimetals is an emerging class of quantum materials, which holds great promise for both technological applications and fundamental discoveries. This stems from their unique combination of physical properties. Indeed, these materials are conducting, like ordinary metals, yet potentially highly tunable, like semiconductors. Most importantly, their nontrivial electronic structure topology is a source of quantum coherence, which is precisely what is needed for macroscopic quantum phenomena.   The goal of the proposed research is to develop full understanding of the interplay of the electronic structure topology of Topological Semimetals with disorder and electron-electron interactions. Disorder and impurities are not simply a nuisance, but are inevitably present, and in fact play a fundamental role in quantum materials. The conductivity of a metal is to a large extent deterrmined by impurities. The integer quantum Hall effect, which is now used to define the resistance standard, would not even exist in a hypothetical perfectly clean material. In Topological Semimetals the additional ingredient of a nontrivial electronic structure topology produces a very interesting interplay with disorder, not present in ordinary metallic materials. The proposed research will aim to uncover macroscopic observable consequences of this interplay, which is essential to understand amd realize the full potential of Topological Semimetals as one of the ingredients of future quantum technologies.