论文标题
扭曲的双层BC $ _3 $：山谷互锁各向异性平坦乐队
Twisted bilayer BC$_3$: Valley interlocked anisotropic flat bands
论文作者
论文摘要
在这里，我们提出了BC $ _3 $，这是一种已合成的石墨烯衍生物，作为一个平台，通过引入不匹配堆叠的Moiré模式来实现异国情调的量子阶段。在扭曲的双层bc $ _3 $中，显示出，从二维到准一维频段结构的交叉结构以扭曲角度作为控制参数进行。这是范德华堆叠系统中指导原理的典型表现：相邻层中Bloch波函数之间的量子干扰对有效的层间隧道具有惊人的作用。有趣的是，准一维以山谷依赖的方式发生。也就是说，山谷指数与准1D方向性之间存在互锁，这使得BC $ _3 $成为Valleytronics设备的合理候选人。此外，山谷互锁的准1D状态的密切相关的态度还原为Kugel-Khomskii模型的有趣变体，其中相互交织的山谷和自由度的自由度潜在地引起了外来的量子相。值得注意的是，由于三倍山谷退化，Kugel-Khomskii模型的这种变体无法在常规固体中实现。
Here we propose BC$_3$, a graphene derivative that has been synthesized, as a platform to realize exotic quantum phases by introducing a moiré pattern with mismatched stacking. In twisted bilayer BC$_3$, it is shown that a crossover from two-dimensional to quasi one-dimensional band structure takes place with the twist angle as a control parameter. This is a typical manifestation of the guiding principle in van der Waals stacked systems: the quantum interference between Bloch wave functions in adjacent layers has a striking effect on the effective interlayer tunneling. Interestingly, quasi one-dimensionalization happens in a valley dependent manner. Namely, there is interlocking between the valley index and the quasi-1D directionality, which makes BC$_3$ a plausible candidate for valleytronics devices. In addition, the strongly correlated regime of the valley interlocked quasi-1D state reduces to an interesting variant of the Kugel-Khomskii model where intertwined valley and spin degrees of freedom potentially induces exotic quantum phases. Notably, this variant of the Kugel-Khomskii model cannot be realized in conventional solids due to the three fold valley degeneracy.
