Engineering correlation, topology and mesoscopic structures in ultra-clean bilayer graphene

Jun Zhu, The Pennsylvania State University

This project aims to open new fronts of strongly correlated phenomena by exploiting the interplay of interactions and topology in ultra-clean 2D materials. The success of this project will produce major experimental advances in the fundamental understanding of several important notions of contemporary condensed matter physics and make significant steps towards the goal of harnessing their potential in the emerging quantum information science and technology. The project builds upon previous discoveries and insights the Zhu lab obtained in the fractional quantum Hall and Hoftstadter butterfly regimes of bilayer graphene and leverages the state-of-the-art van nanofabrication capabilities of our lab. The project has four objectives. The first objective aims to discover phase transitions between competing quantum Hall and moire physics in the Hoftstadter regime. The second objective seeks to realize a quantum spin Hall insulator phase by tuning the relative strength of long-ranged and short-ranged Coulomb interactions and use the system to understand the behavior of interacting helical Luttinger liquid. The third objective of the project aims to explore the possibility of valley isospin magnetism of multi-component composite fermions. The fourth objective aims to obtain fundamental knowledge on fractional and non-Abelian braiding statistics, which are cornerstone understandings of topological qubits, through the construction and study of high-quality quantum Hall interferometers. Proposed experiments combine clean van der Waals heterostructure building, sophisticated mesoscopic engineering and low-temperature precision transport measurements to pursue several timely, frontier topics of condensed matter physics. Measurements will make use of the National Hight Magnetic Field facilities.