Phinney I Y, Bandurin D A, Collignon C, Dmitriev I A, Taniguchi T, Watanabe K, Jarillo-Herrero P
Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Physics Department, University of Regensburg, 93040, Regensburg, Germany.
Phys Rev Lett. 2021 Jul 30;127(5):056802. doi: 10.1103/PhysRevLett.127.056802.
Twisted bilayer graphene (TBG) provides an example of a system in which the interplay of interlayer interactions and superlattice structure impacts electron transport in a variety of nontrivial ways and gives rise to a plethora of interesting effects. Understanding the mechanisms of electron scattering in TBG has, however, proven challenging, raising many questions about the origins of resistivity in this system. Here we show that TBG exhibits high-temperature magneto-oscillations originating from the scattering of charge carriers between TBG minivalleys. The amplitude of these oscillations reveals that interminivalley scattering is strong, and its characteristic timescale is comparable to that of its intraminivalley counterpart. Furthermore, by exploring the temperature dependence of these oscillations, we estimate the electron-electron collision rate in TBG and find that it exceeds that of monolayer graphene. Our study demonstrates the consequences of the relatively small size of the superlattice Brillouin zone and Fermi velocity reduction on lateral transport in TBG.
扭曲双层石墨烯（TBG）提供了一个系统示例，其中层间相互作用和超晶格结构的相互作用以多种非平凡的方式影响电子输运，并产生了大量有趣的效应。然而，事实证明，理解TBG中电子散射的机制具有挑战性，引发了许多关于该系统中电阻率起源的问题。在此，我们表明TBG表现出源自TBG微谷之间电荷载流子散射的高温磁振荡。这些振荡的幅度表明谷间散射很强，其特征时间尺度与其谷内对应物相当。此外，通过探究这些振荡的温度依赖性，我们估计了TBG中的电子 - 电子碰撞率，发现它超过了单层石墨烯的碰撞率。我们的研究证明了超晶格布里渊区相对较小的尺寸和费米速度降低对TBG横向输运的影响。
