Electrons behave like a classical fluid with a momentum distribution function that varies slowly in space and time when the quantum-mechanical carrier-carrier scattering dominates over all other scattering processes. Recent experiments in monolayer and bilayer graphene have reported signatures of such hydrodynamic electron behavior in ultraclean devices. In this theoretical work, starting from a microscopic treatment of electron-electron, electron-phonon, and electron-impurity interactions within the random phase approximation, we demonstrate that monolayer and bilayer graphene both host two different hydrodynamic regimes. We predict that the hydrodynamic window in bilayer graphene is stronger than in monolayer graphene, and has a characteristic “v shape” as opposed to a “lung shape.” Finally, we collapse experimental data onto a universal disorder-limited theory, demonstrating that the observed violation of the Wiedemann-Franz law in monolayers occurs in a regime dominated by impurity-induced electron-hole puddles.

中文翻译：

---

从散射速率理论确定单层和双层石墨烯中的流体动力学窗口

当量子机械载流子-载流子散射在所有其他散射过程中占主导地位时，电子的行为类似于具有动量分布函数的经典流体，该动量分布函数在空间和时间上缓慢变化。最近在单层和双层石墨烯中进行的实验已经报道了这种超净装置中流体动力电子行为的特征。在这项理论工作中，从对随机相近似内的电子-电子，电子-声子和电子-杂质相互作用的微观处理开始，我们证明了单层和双层石墨烯都具有两种不同的流体动力学机制。我们预测双层石墨烯中的流体力学窗口比单层石墨烯中的流体力学窗口要强，并且具有与“肺部形状”相对的特征“ v形”。最后，