The line shape of the double-resonant $2D$ Raman mode in bilayer graphene is often considered to be characteristic for a certain laser excitation energy. Here, in a joint experimental and theoretical study, we analyze the dependence of the double-resonant Raman scattering processes in bilayer graphene on the electronic broadening parameter $\gamma$. We demonstrate that the ratio between symmetric and anti-symmetric scattering processes sensitively depends on the lifetime of the electronic states, explaining the experimentally observed variation of the complex $2D$-mode line shape.

中文翻译：

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双共振拉曼散射中双层石墨烯中的可调谐量子干涉

双层石墨烯中双共振$2D$拉曼模式的线形通常被认为是特定激光激发能量的特征。在这里，在联合实验和理论研究中，我们分析了双层石墨烯中双共振拉曼散射过程对电子展宽参数 $\gamma$ 的依赖性。我们证明对称和反对称散射过程之间的比率敏感地取决于电子态的寿命，解释了实验观察到的复杂 $2D$-模式线形状的变化。