TYC Online Seminar: Hartree theory calculations of quasiparticle properties in twisted bilayer graphene

Abstract:

Recently correlated insulating states and superconductivity were observed in twisted bilayer graphene (tBLG). A detailed understanding of interacting electrons in tBLG near the magic angle is required to gain insights into the physical origin of the observed broken symmetry phases. We performed extensive atomistic Hartree theory calculations of the electronic properties of tBLG in the (semi-)metallic phase as function of doping and twist angle. Specifically, we calculated the quasiparticle properties, such as the band structure, density of states (DOS) and local density of states (LDOS), which are directly accessible in photoemission and tunnelling spectroscopy experiments. We found that quasiparticle properties change significantly upon doping—an effect which is not captured by tight-binding theory. In particular, we observe that the partially occupied bands flatten significantly which enhances the density of states at the Fermi level. 

Reference: Zachary A H Goodwin et al 2020 Electron. Struct. 2 034001