论文标题
双层石墨烯Moiré超级晶格中的umklapp电子电子散射
Umklapp electron-electron scattering in bilayer graphene moiré superlattice
论文作者
论文摘要
最近的实验进步以高度排列的石墨烯和六角硼（HBN）高度排列的异质结构（HBN）的高度排列异质结构中的弹道电子传输的观察到了标志。在这里，我们预测，与HBN底物对齐的高质量石墨烯双层具有$ T^2 $依赖性电阻率，这是由Umklapp Electron-Electron（UEE）散射从MoiréSuperSlattice散射引起的，也就是说，这是由一对电子经历的Bragg散射的动量踢。大量的UEE散射出现在$ p $的双层以上的阈值密度上方，这取决于石墨烯和HBN之间的扭角，其对电阻率的贡献随孔密度迅速增长，直到其达到峰值，其峰值随超值延长时期的峰值变化而变化。我们还分析了双层和三角翘曲中静电诱导的带隙的影响，它在电子分散体上增强了电子 - 电子umklapp散射。
Recent experimental advances have been marked by the observations of ballistic electron transport in moiré superlattices in highly aligned heterostructures of graphene and hexagonal boron nitride (hBN). Here, we predict that a high-quality graphene bilayer aligned with an hBN substrate features $T^2$-dependent resistivity caused by umklapp electron-electron (Uee) scattering from the moiré superlattice, that is, a momentum kick by Bragg scattering experienced by a pair of electrons. Substantial Uee scattering appears upon $p$-doping of the bilayer above a threshold density, which depends on the twist angle between graphene and hBN, and its contribution towards the resistivity grows rapidly with hole density until it reaches a peak value, whose amplitude changes non-monotonically with the superlattice period. We also analyse the influence of an electrostatically induced bandgap in the bilayer and trigonal warping it enhances in the electron dispersion on the electron-electron umklapp scattering.
