Zhang Xi, Tsai Kan-Ting, Zhu Ziyan, Ren Wei, Luo Yujie, Carr Stephen, Luskin Mitchell, Kaxiras Efthimios, Wang Ke
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Phys Rev Lett. 2021 Oct 15;127(16):166802. doi: 10.1103/PhysRevLett.127.166802.
Layers of two-dimensional materials stacked with a small twist angle give rise to beating periodic patterns on a scale much larger than the original lattice, referred to as a "moiré superlattice." Here, we demonstrate a higher-order "moiré of moiré" superlattice in twisted trilayer graphene with two consecutive small twist angles. We report correlated insulating states near the half filling of the moiré of moiré superlattice at an extremely low carrier density (∼10^{10} cm^{-2}), near which we also report a zero-resistance transport behavior typically expected in a 2D superconductor. The full-occupancy (ν=-4 and ν=4) states are semimetallic and gapless, distinct from the twisted bilayer systems.
以小扭转角堆叠的二维材料层会在比原始晶格大得多的尺度上产生跳动的周期性图案，称为“莫尔超晶格”。在此，我们展示了在具有两个连续小扭转角的扭曲三层石墨烯中的高阶“莫尔之莫尔”超晶格。我们报告了在极低载流子密度（~10^{10} cm^{-2}）下莫尔之莫尔超晶格半填充附近的关联绝缘态，在该绝缘态附近我们还报告了二维超导体中通常预期的零电阻输运行为。全占据（ν = -4和ν = 4）态是半金属且无带隙的，这与扭曲双层系统不同。
