Iwasaki Takuya, Nakaharai Shu, Wakayama Yutaka, Watanabe Kenji, Taniguchi Takashi, Morita Yoshifumi, Moriyama Satoshi
International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan.
International Center for Materials Nanoarchitectonics (WPI-MANA), NIMS, Tsukuba, Ibaraki 305-0044, Japan.
Nano Lett. 2020 Apr 8;20(4):2551-2557. doi: 10.1021/acs.nanolett.9b05332. Epub 2020 Mar 26.
Graphene/hexagonal boron nitride (hBN) moiré superlattices have attracted interest for use in the study of many-body effects and fractal physics in Dirac fermion systems. Many exotic transport properties have been intensively examined in such superlattices, but previous studies have not focused on single-carrier transport. The investigation of the single-carrier behavior in these superlattices would lead to an understanding of the transition of single-particle/correlated phenomena. Here, we show the single-carrier transport in a high-quality bilayer graphene/hBN superlattice-based quantum dot device. We demonstrate remarkable device controllability in the energy range near the charge neutrality point (CNP) and the hole-side satellite point. Under a perpendicular magnetic field, Coulomb oscillations disappear near the CNP, which could be a signature of the crossover between Coulomb blockade and quantum Hall regimes. Our results pave the way for exploring the relationship of single-electron transport and fractal quantum Hall effects with correlated phenomena in two-dimensional quantum materials.
石墨烯/六方氮化硼（hBN）莫尔超晶格在狄拉克费米子系统的多体效应和分形物理学研究中受到关注。许多奇异的输运特性已在此类超晶格中得到深入研究，但先前的研究并未聚焦于单载流子输运。对这些超晶格中单载流子行为的研究将有助于理解单粒子/关联现象的转变。在此，我们展示了基于高质量双层石墨烯/hBN超晶格的量子点器件中的单载流子输运。我们证明了在电荷中性点（CNP）和空穴侧卫星点附近的能量范围内，器件具有显著的可控性。在垂直磁场下，CNP附近的库仑振荡消失，这可能是库仑阻塞和量子霍尔 regime之间交叉的一个标志。我们的结果为探索二维量子材料中与关联现象相关的单电子输运和分形量子霍尔效应之间的关系铺平了道路。
