论文标题
长期电子电子相互作用对于扭曲双层石墨烯的磁相图的重要性
Importance of long-ranged electron-electron interactions for the magnetic phase diagram of twisted bilayer graphene
论文作者
论文摘要
电子 - 电子相互作用本质上是长期范围的，但是许多强相互作用的模型仅考虑了短距离的相互作用。在这里，我们介绍了原子计算的结果，包括扭曲双层石墨烯的磁相图，包括长量和短额的电子电子相互作用，并证明当忽略长期相互作用时，获得了定性不同的结果。特别是，我们使用Hartree理论增强了Hubbard相互作用，并在魔术角附近计算了一系列掺杂水平和扭曲角度的相互作用旋转易感性，以识别主要的磁性不稳定性。在魔法角度，发现大多数抗铁磁秩序，而铁磁词则以其他扭曲角度占主导地位。此外，长期相互作用显着增加了可以预期强相关现象的扭曲角窗口。这些发现与可用的实验数据非常吻合。
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 magic angle to identify the dominant magnetic instabilities. At the magic angle, mostly anti-ferromagnetic 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.
