Speaker
Description
Recent experimental observations of correlated phases in magic-angle twisted bilayer graphene (MATBG) strongly indicate the enhanced importance of electronic correlations in this flat band system. Twist in graphene layers in MATBG results in the formation of moiré patterns with length scales much larger than the atomic distance between carbon atoms in individual layers. It is often believed that most of the crucial physical properties occur at the moiré length scale. Thus a natural first step towards treating correlations is to construct a tight-binding model based on Wannier functions localized on the effective moiré lattice. However, the construction of such a model for twisted bilayer graphene is under debate due to the topological character of the energy bands. We discuss the accuracy of such Wannier descriptions for the widely-used Bistritzer and MacDonald model for a range of twist-angles and values of relaxations. Our study provides a starting point for investigating interaction effects in MATBG.
