论文标题
电流携带石墨烯的平面光学声子模式
In-plane optical phonon modes of current-carrying graphene
论文作者
论文摘要
在这项工作中，我们研究了携带电流的单层石墨烯的面内光学声子模式，该石墨烯与$π$电子气体的耦合很强。与非平衡型锥体电子特征态相比，与非平衡性占用相比，这种模式有望发生频移，而流动的$π$电子气体。可以通过称为Kohn异常的声子模式分散的斜率突然变化来识别大型电子 - 音波耦合（EPC），该耦合的斜率被称为Kohn Anomalo，主要发生在（i）（i）（i）平面纵向/横向光学/横向光学（lo/to/to）模式（Brillouin Zone（bz）中心（BZ）中心（$γ$ copte）和$ k $ k $ k的$ kere（$）和（$）$ KIONE（$）。我们表明，DC电流将旋转对称性的破坏会导致不同的频率转移到$γ$ - 至$γ$ -LO模式。更具体地说，DC电流以$γ$点的能用式模式退化，理想情况下将表现为拉曼G峰的分裂。
In this work, we study the in-plane optical phonon modes of current-carrying single-layer graphene whose coupling to the $π$ electron gas is strong. Such modes are expected to undergo a frequency shift compared to the non-current-carrying state due to the non-equilibrium occupation of the Dirac cone electronic eigen-states with the flowing $π$ electron gas. Large electron-phonon coupling (EPC) can be identified by an abrupt change in the slope of the phonon mode dispersion known as the Kohn anomaly, which mainly occurs for (i) the in-plane longitudinal/transverse optical (LO/TO) modes at the Brillouin zone (BZ) center ($Γ$ point), and (ii) the TO modes at the BZ corners ($K$ points). We show that the breaking of the rotational symmetry by the DC current results in different frequency shifts to the $Γ$-TO and $Γ$-LO modes. More specifically, the DC current breaks the TO-LO mode degeneracy at the $Γ$ point which ideally would be manifested as the splitting of the Raman G peak.
