Importance of long-ranged electron-electron interactions for the magnetic phase diagram of twisted bilayer graphene

摘要: Electron-electron interactions are intrinsically long ranged, but many models of strongly interacting electrons only take short-ranged into account. Here, we present results atomistic calculations including both long-ranged and electron-electron for the magnetic phase diagram twisted bilayer graphene demonstrate that qualitatively different obtained when neglected. In particular, use Hartree theory augmented with Hubbard calculate spin susceptibility at a range doping levels twist angles near magic angle to identify dominant instabilities. At angle, mostly anti-ferromagnetic order is found, while ferromagnetism dominates other angles. Moreover, significantly increase window in which strong correlation phenomena can be expected. These findings good agreement available experimental data.