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arXiv 2001.10427cond-mat.mes-hall
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30来自化学气相沉积的$^\circ$ -扭曲双层石墨烯准晶体

30$^\circ$-twisted bilayer graphene quasicrystals from chemical vapor deposition

Sergio Pezzini, Vaidotas Miseikis, Giulia Piccinini, Stiven Forti, Simona Pace, Rebecca Engelke, Francesco Rossella, Kenji Watanabe, Takashi Taniguchi, Philip Kim, Camilla Coletti

摘要:

原子级薄晶体的人工堆叠在剥离薄片的相对取向的控制和再现性方面受到固有的限制。当系统的性质严重依赖于扭转角时,这个缺点尤其严重,例如由两个石墨烯层旋转30 ° $^\circ$形成的十二方准晶的情况。在这里,我们表明,大面积的30 $^\circ$旋转双层石墨烯可以确定性地通过化学气相沉积在铜上生长,消除了人工组装的需要。准晶很容易转移到任意衬底上,并集成在高质量的hBN封装的异质结构中,我们将其加工成双栅极器件,其载流子迁移率高达$10^5$ cm $^2$ /Vs。从低温磁输运中,我们发现石墨烯准晶有效地表现为非耦合石墨烯层,显示出8倍简并量子霍尔态:该结果表明,由先前的光电发射实验检测到的狄拉克锥复制品对电输运没有贡献。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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