Despoja Vito, Radović Ivan, Politano Antonio, Mišković Zoran L
Institute of Physics, Bijenička 46, Zagreb HR-10000, Croatia.
Donostia International Physics Center (DIPC), P. Manuel de Lardizabal, 20018 San Sebastian, Basque Country, Spain.
Nanomaterials (Basel). 2020 Apr 8;10(4):703. doi: 10.3390/nano10040703.
The excitation spectrum in the region of the intraband (Dirac plasmon) and interband ( π plasmon) plasmons in graphene/Pt-skin terminated Pt 3 Ni(111) is reproduced by using an method and an empirical model. The results of both methods are compared with experimental data. We discover that metallic screening by the Pt layer converts the square-root dispersion of the Dirac plasmon into a linear acoustic-like plasmon dispersion. In the long-wavelength limit, the Pt electron excitations completely quench the π plasmon in graphene at about 4.1 eV, that is replaced by a broad peak at about 6 eV. Owing to a rather large graphene/Pt-skin separation (≈3.3 Å), the graphene/Pt-skin hybridization becomes weak at larger wave vectors, so that the π plasmon is recovered with a dispersion as in a free-standing graphene.
利用一种方法和一个经验模型再现了石墨烯/Pt 表皮终止的 Pt₃Ni(111)中带内（狄拉克等离子体激元）和带间（π 等离子体激元）等离子体激元区域的激发光谱。将这两种方法的结果与实验数据进行了比较。我们发现，Pt 层的金属屏蔽将狄拉克等离子体激元的平方根色散转变为类似线性声学的等离子体激元色散。在长波长极限下，Pt 电子激发在约 4.1 eV 处完全淬灭了石墨烯中的 π 等离子体激元，取而代之的是在约 6 eV 处的一个宽峰。由于石墨烯/Pt 表皮间距相当大（约 3.3 Å），在较大波矢处石墨烯/Pt 表皮杂化变弱，从而 π 等离子体激元以类似于独立石墨烯中的色散得以恢复。
