论文标题
扭曲的三层石墨烯的超级低能量有效理论
Supermoiré low-energy effective theory of twisted trilayer graphene
论文作者
论文摘要
堆叠三个具有扭曲的石墨烯的单层通常会产生两个moiré图案。然后，莫伊尔结构的莫伊尔结构在更大的距离处出现，三层定期重新调整。我们在这里设计了一种有效的低能理论，可以描述比Moiré长度尺度更大的距离的光谱。在基础石墨烯的每个山谷中，该理论包括一个零圆锥，位于$ {\bfγ} _m $ $点的MoiréBrillouinZone和两个弱差点，分别为$ {\ bf k} _m $ $和$ {\ bf k}'_ m $。速度和小间隙在Moiré单位单元中表现出空间依赖性，具有确保仪表不变性的非亚伯连接电位。所得模型是在数值上求解的，并获得了完全连接的光谱，该光谱由时间反转和双重旋转对称性的组合保护。
Stacking three monolayers of graphene with a twist generally produces two moiré patterns. A moiré of moiré structure then emerges at larger distance where the three layers periodically realign. We devise here an effective low-energy theory to describe the spectrum at distances larger than the moiré lengthscale. In each valley of the underlying graphene, the theory comprises one Dirac cone at the ${\bf Γ}_M$ point of the moiré Brillouin zone and two weakly gapped points at ${\bf K}_M$ and ${\bf K}'_M$. The velocities and small gaps exhibit a spatial dependence in the moiré-of-moiré unit cell, entailing a non-abelian connection potential which ensures gauge invariance. The resulting model is numerically solved and a fully connected spectrum is obtained, which is protected by the combination of time-reversal and twofold-rotation symmetries.
