Download or read book Nature of the Electronic States in Monolayer WTe2 written by Bosong Sun and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum materials are those with essential properties that cannot be described in terms of semiclassical particles and elementary quantum mechanics. In these materials, strong electronic correlations or electronic order, such as superconducting or magnetic order, or topologically nontrivial electronic structure play a key role. The study of two-dimensional quantum materials was triggered by the discovery of graphene as the first stable, isolated atomic monolayer. Beyond graphene, the emergence of other atomically thin two-dimensional materials, such as transition metal dichalcogenides, has offered a promising platform for realizing tunable quantum states. This thesis focuses on the nature of electronic states in monolayer tungsten ditelluride (WTe2). In the first part, I will introduce the discovery of the quantum spin Hall insulator (QSHI) state and superconducting state in single layer WTe2. There, the carrier density-dependent phase transition from a topological insulator to superconductor hints at BCS-like excitonic condensation in this exotic material. In the second part, I will address studies of the possibility of forming excitons and an exciton condensate in monolayer WTe2 with both experimental and theoretical evidence. Then, I will show studies of stacking induced ferroelectricity in few-layer WTe2 and illustrate that bilayer WTe2 is another potential excitonic insulator candidate with further study on its insulating state. At the end, I will talk about a selection of other approaches to studying two-dimensional materials and give an outlook to future opportunities in the study.