Wu Reng-Lai, Quan Jun, Sun Mengtao
School of Physical Science and Technology, Lingnan Normal University, Zhanjiang, 524048, P.R. China.
School of Mathematics and Physics, Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, University of Science and Technology Beijing, Beijing, 100083, P.R. China.
Sci Rep. 2018 Aug 22;8(1):12563. doi: 10.1038/s41598-018-30877-w.
Based on the self-consistent linear response theory, the plasmon-energy absorption in linear atomic chain are studied by using the tight-binding approximation. Results indicate that the eigen-frequency of the plasmon is uninfluenced by the external electric potential, but the plasmon modes excited by various electric potentials are obviously different. Each mode of plasmon corresponds to one kind of eigen-charge distribution. When the plasmon mode is excited, the resonant charge will show a distribution characteristic the same as the one of eigen charge. And the plasmon mode can be precisely controlled by external electric potential if the eigen-charge distribution at such plasmon is known. The relationship between plasmon-energy absorption and atom number are also affected by the external electric potential. However, most of the other studies only show the normal case that the plasmon-energy absorption increases with the atom number increasing. Here, we demonstrate that the normal case commonly occurs under monotone increasing potential. And abnormal case may occur under monotone decreasing potential, ie, the plasmon-energy absorption will decrease with the atom number increasing. But, in the presence of arbitrary potential applied to the same atomic chain, the plasmon-energy absorption will always increase with the electron number increasing.
基于自洽线性响应理论，采用紧束缚近似研究了线性原子链中的等离激元能量吸收。结果表明，等离激元的本征频率不受外部电势影响，但不同电势激发的等离激元模式明显不同。每种等离激元模式对应一种本征电荷分布。当等离激元模式被激发时，共振电荷将呈现与本征电荷相同的分布特征。并且，如果已知等离激元处的本征电荷分布，等离激元模式可由外部电势精确控制。等离激元能量吸收与原子数之间的关系也受外部电势影响。然而，大多数其他研究仅表明等离激元能量吸收随原子数增加而增加这种正常情况。在此，我们证明正常情况通常在电势单调增加时出现。而在电势单调降低时可能出现异常情况，即等离激元能量吸收将随原子数增加而降低。但是，当对同一原子链施加任意电势时，等离激元能量吸收将始终随电子数增加而增加。
