论文标题
扭曲的双层石墨烯的拉曼光谱靠近魔术角
Raman spectra of twisted bilayer graphene close to the magic angle
论文作者
论文摘要
In this work, we study the Raman spectra of twisted bilayer graphene samples as a function of their twist-angles ($θ$), ranging from 0.03$^\circ$ to 3.40$^\circ$, where local $θ$ are determined by analysis of their associated moire superlattices, as imaged by scanning microwave impedance microscopy.使用了三种标准激发激光线（457、532和633 nm波长），并考虑了主要的拉曼活性石墨烯带（G和2D）。我们的结果表明，无论激光激发波长如何，电子 - 音波相互作用都会影响G频段的线宽接近魔法角度。同样，$θ$ <1 $^\ circ $制度中的2D带线路是由晶格决定的，并取决于bernal（AB和BA）堆叠双层石墨烯和菌株soliton区域（SP）。我们提出了一个几何模型来解释2D线形变化，从中，我们估计朝魔法角度移动时的SP宽度。
In this work, we study the Raman spectra of twisted bilayer graphene samples as a function of their twist-angles ($θ$), ranging from 0.03$^\circ$ to 3.40$^\circ$, where local $θ$ are determined by analysis of their associated moire superlattices, as imaged by scanning microwave impedance microscopy. Three standard excitation laser lines are used (457, 532, and 633 nm wavelengths), and the main Raman active graphene bands (G and 2D) are considered. Our results reveal that electron-phonon interaction influences the G band's linewidth close to the magic angle regardless of laser excitation wavelength. Also, the 2D band lineshape in the $θ$ < 1$^\circ$ regime is dictated by crystal lattice and depends on both the Bernal (AB and BA) stacking bilayer graphene and strain soliton regions (SP). We propose a geometrical model to explain the 2D lineshape variations, and from it, we estimate the SP width when moving towards the magic angle.
