2020/12/31 by Lennart Klebl, Zachary A. H. Goodwin, Arash A. Mostofi +2
Materials Science · Physics and Astronomy · #Bilayer graphene #Condensed matter physics #Electron #Electronic correlation #Ferromagnetism #Geometry #Graphene #Graphene research and applications #Magic angle #Magnetic properties of thin films #Phase (matter) #Phase diagram #Physics #Quantum and electron transport phenomena #Quantum mechanics #Spectral line #Spin (aerodynamics) #Twist #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.103.195127
published as Phys. Rev. B 103, 195127 (2021) · 7 pages, 4 figures
openalex created_date 2021/01/05 · arxiv created 2021/04/28 · openalex publication_date 2021/05/12 · arxiv updated 2021/05/19 · openalex updated_date 2026/08/05
Electron-electron interactions are intrinsically long ranged, but many models of strongly interacting electrons only take short-ranged interactions into account. Here, we present results of atomistic calculations including both long-ranged and short-ranged electron-electron interactions for the magnetic phase diagram of twisted bilayer graphene and demonstrate that qualitatively different results are obtained when long-ranged interactions are neglected. In particular, we use Hartree theory augmented with Hubbard interactions and calculate the interacting spin susceptibility at a range of doping levels and twist angles near the first magic angle to identify the dominant magnetic instabilities. At the magic angle, mostly antiferromagnetic order is found, while ferromagnetism dominates at other twist angles. Moreover, long-ranged interactions significantly increase the twist angle window in which strong correlation phenomena can be expected. These findings are in good agreement with available experimental data.