Designing flat bands by strain

Abstract

Magic angle twisted bilayer graphene (MATBG) is an exciting new system for flat electronic bands and correlated physics. However, heterostrains are ubiquitous in the TBG samples, and their role on the electronic properties has not been clear. Here, the authors show that heterostrains generically broaden the flat bands in MATBG. This explains many puzzling results from transport and scanning tunneling spectroscopy experiments. Furthermore, one can utilize the heterostrain to engineer highly flexible moir\'e flat bands in bilayer transition metal dichalcogenides, suggesting another platform to be exploited.