Band structure and insulating states driven by Coulomb interaction in twisted bilayer graphene
Band structure and insulating states driven by Coulomb interaction in twisted bilayer graphene
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DOI：
10.1103/physrevb.102.045107
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发表时间：
2020-07-06
影响因子：
3.7
通讯作者：
Guinea, Francisco
中科院分区：
文献类型：
--
作者：
Cea, Tommaso;Guinea, Francisco
我们分析了在一个魔角附近扭曲的石墨烯双层的相图。我们考虑了在自洽Hartree-Fock近似中处理的远程库仑相互作用的影响，并研究了任意带填充。我们发现了一个丰富的相图，有不同的破缺对称相，尽管它们不一定显示费米能量的间隙。在对称性破缺相中，静电势对带的形状和间隙有重要的影响。结果表明，实验观察到的非超导破缺对称相是由远距离交换相互作用引起的。
We analyze the phase diagram of twisted graphene bilayers near a magic angle. We consider the effect of the long-range Coulomb interaction, treated within the self-consistent Hartree-Fock approximation, and we study arbitrary band fillings. We find a rich phase diagram, with different broken symmetry phases, although they do not show necessarily a gap at the Fermi energy. There are nontrivial effects of the electrostatic potential on the shape and the gaps of the bands in the broken symmetry phases. The results suggest that the nonsuperconducting broken symmetry phases observed experimentally are induced by the long-range exchange interaction.