论文标题
30美元
30$^\circ$-twisted bilayer graphene quasicrystals from chemical vapor deposition
论文作者
论文摘要
原子上薄晶体的人工堆叠在控制和可重复性方面具有固有局限性。当系统的性质严重取决于扭角时，这种缺点尤其严重，就像在两个石墨烯层旋转30 $^\ circ $形成的十二型准晶体的情况下一样。在这里，我们表明，大面积30 $^\ CIRC $分流的双层石墨烯可以通过化学蒸气在Cu上确定生长，从而消除了人工组装的需求。准晶体很容易转移到任意基板上，并集成到高质量的HBN封装异质结构中，我们将其处理到表现出载体移动性高达$ 10^5 $ CM $ $^2 $/vs的双门控设备中。从低温的磁转运运动中，我们发现石墨烯准晶体有效地表现为未偶联的石墨烯层，显示了8倍退化的量子霍尔指出：此结果表明，先前的照片发射实验检测到的DIRAC锥复制品并不有助于电气传输。
The artificial stacking of atomically thin crystals suffers from intrinsic limitations in terms of control and reproducibility of the relative orientation of exfoliated flakes. This drawback is particularly severe when the properties of the system critically depend on the twist angle, as in the case of the dodecagonal quasicrystal formed by two graphene layers rotated by 30$^\circ$. Here we show that large-area 30$^\circ$-rotated bilayer graphene can be grown deterministically by chemical vapor deposition on Cu, eliminating the need of artificial assembly. The quasicrystals are easily transferred to arbitrary substrates and integrated in high-quality hBN-encapsulated heterostructures, which we process into dual-gated devices exhibiting carrier mobility up to $10^5$ cm$^2$/Vs. From low-temperature magnetotransport, we find that the graphene quasicrystals effectively behave as uncoupled graphene layers, showing 8-fold degenerate quantum Hall states: this result indicates that the Dirac cones replica detected by previous photo-emission experiments do not contribute to the electrical transport.
