论文标题
石墨烯拉曼光谱中的费米共振
Fermi resonance in the Raman spectrum of graphene
论文作者
论文摘要
我们报告了与与石墨烯接触的铬纳米颗粒的存在相关的拉曼石墨烯的拉曼光谱中1608 cm $^{ - 1} $处的强烈异常峰的观察。用电子光束轰击表明，这个峰与研究良好的D $'$峰不同，因为在石墨烯中会产生缺陷。新峰被发现不分散。我们认为，铬原子与碳原子的键合化了平面光学（ZO）声子模式，以至于其浓度的频率降至$2Ω_{\ rm zo} \simΩ拉曼活跃的E $ _ {\ rm 2g} $模式的模式。因此，观察到的新峰归因于2ZO模式，该模式遵循一种称为费米共振的机制变为拉曼活性。第一原则计算石墨烯/CR接口的振动和非谐属性支持此情况。
We report the observation of an intense anomalous peak at 1608 cm$^{-1}$ in the Raman spectrum of graphene associated to the presence of chromium nanoparticles in contact with graphene. Bombardment with an electron beam demonstrates that this peak is distinct from the well studied D$'$ peak appearing as defects are created in graphene; the new peak is found non dispersive. We argue that the bonding of chromium atoms with carbon atoms softens the out-of-plane optical (ZO) phonon mode, in such a way that the frequency of its overtone decreases to $2ω_{\rm ZO}\simω_{\rm G}$, where $ω_{\rm G}$=1585~cm$^{-1}$ is the frequency of the Raman-active E$_{\rm 2g}$ mode. Thus, the observed new peak is attributed to the 2ZO mode which becomes Raman-active following a mechanism known as Fermi resonance. First-principles calculations on vibrational and anharmonic properties of the graphene/Cr interface support this scenario.
