论文标题
Moiré力学上的电力背部
Electric backaction on moiré mechanics
论文作者
论文摘要
范德华层之间的格子不匹配会产生moiré图案和随后的电子带重建。当双层充电时，一层相对于另一层的滑动运动会产生电动泵。在这里，我讨论了相互的过程：电压偏置会产生层剪切机械力。效果是从最低阶校正到与外场中的电子结合的机械作用的。在扭曲的双层石墨烯中，新的机械力被证明垂直于施加的场（由于c $ _2 $ symmetries交换了层），并且与从中性测得的电荷密度成正比。当化学电位在拓扑量化引起的摩尔电势张开时，这是完全正确的，而当化学势越过模型中的平坦带（包括自持式的Hartree相互作用）中时，这是正确的。在机械设备中，应表现为在系统充电时层之间摩擦的明显增强。在魔术角上，以$ \ Mathcal {e} _C \ sim $ kV/cm为单位估算了层的滑动运动的划分字段。
A lattice mismatch between Van der Waals layers produces a moiré pattern and a subsequent electron band reconstruction. When the bilayer is charged, the sliding motion of one layer with respect to the other produces electric pumping. Here I discuss the reciprocal process: that a voltage bias produces a layer-shear mechanical force. The effect is deduced from the lowest-order correction to the mechanical action by the coupling with electrons in an external field. In twisted bilayer graphene the new mechanical force is shown to be perpendicular to the applied field (due to C$_2$ symmetries exchanging the layers) and proportional to the charge density measured from neutrality. This is strictly true when the chemical potential is within a gap opened by the moiré potential due to a topological quantization, and approximately true when the chemical potential crosses the flat bands in a model including the self-consistent Hartree interaction. In a mechanical device the effect should be manifested as an apparent enhancement of the friction between layers when the system is charged. Depinning fields for the sliding motion of the layers are estimated in the order of $\mathcal{E}_c\sim$ kV/cm around the magic angle.
