Raman Linewidth Contributions from Four-Phonon and Electron-Phonon Interactions in Graphene
Raman Linewidth Contributions from Four-Phonon and Electron-Phonon Interactions in Graphene
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DOI：
10.1103/physrevlett.128.045901
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发表时间：
2022-01-25
影响因子：
8.6
通讯作者：
Ruan, Xiulin
中科院分区：
文献类型：
--
作者：
Han, Zherui;Yang, Xiaolong;Ruan, Xiulin
拉曼峰位置和线宽提供了对材料中声子非调和性和电子-声子相互作用的深入了解。对于单层石墨烯，先前的第一性原理计算得出线宽随温度升高而减小，这与测量结果相反。在这里，我们明确地考虑了四声子非调和性、声子重正化和电子-声子耦合，并发现所有这些对于成功解释我们悬浮石墨烯样品在宽温度范围内的G峰频移和线宽都很重要。四声子散射有助于显著的线宽随温度增加，而电子-声子相互作用的温度依赖性被发现在掺杂阈值以上被逆转(普朗克常数超过2 PI omega（G)/2，其中omega(G)是G声子的频率）。
The Raman peak position and linewidth provide insight into phonon anharmonicity and electron-phonon interactions in materials. For monolayer graphene, prior first-principles calculations have yielded decreasing linewidth with increasing temperature, which is opposite to measurement results. Here, we explicitly consider four-phonon anharmonicity, phonon renormalization, and electron-phonon coupling, and find all to be important to successfully explain both the G peak frequency shift and linewidths in our suspended graphene sample over a wide temperature range. Four-phonon scattering contributes a prominent linewidth that increases with temperature, while temperature dependence from electron-phonon interactions is found to be reversed above a doping threshold (PLANCK CONSTANT OVER TWO PI omega(G)/2, with omega(G) being the frequency of the G phonon).