Multi-orbital topological Anderson models for twisted bilayer graphene.

Abstract

Magic-angle twisted bilayer graphene (MATBG) is a fascinating system that displays a plethora of intriguing physical phenomena such as correlated insulators, superconductivity, and unconventional quantum Hall effects, among others. Several recent experiments have demonstrated the rich electronic properties of MATBG, which exhibits correlated insulating and superconducting phases. In spite of such a vast amount of experimental data, there are still several open questions regarding the theoretical description of this material in different regimes. While there is some consensus that these phenomena are related to the formation of flat bands near the Fermi level captured by non-interacting band structure models, the description of MATBG as a strongly correlated system is nonetheless challenging. In this Master's project, we propose a description of the correlated electronic properties of MATBG in terms of multi-orbital topological Anderson models (both as a single impurity and as a periodic Anderson lattice), building on the framework recently developed describing MATBG as a topological heavy fermion problem. By employing a combination of analytical and numerical methods, we aim to study the low-energy physics of such models and identify the emergent energy scales and the nature of the Mott transition. We expect that our results can provide some additional insight into the nature of the electronic states in MATBG and suggest new avenues for experimental investigation of this fascinating material system.