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arXiv 1409.3472cond-mat.mes-hallcond-mat.mtrl-sci
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在纯的和过渡金属掺杂的贵金属纳米链阵列中调谐等离子体激元激发

Tuning plasmon excitations in pure and transition metal-doped arrays of noble metal nanochains

Neha Nayyar, Volodymyr Turkowski, Talat S. Rahman

摘要:

采用含时密度泛函理论(TDDFT)方法研究了不同耦合链数和不同过渡金属(TM)原子掺杂情况下耦合贵金属纳米链的等离子体性质.我们发现,随着阵列中链的数量增加,等离子体激元峰从亚电子伏特向可见光范围移动。随着TM原子掺杂的增加,可见吸收带变宽,这是由于形成了额外的等离子体峰。的光学响应是非常敏感的掺杂原子的类型,它们的数量和位置,特别是,额外的峰值是最明显的情况下,弱掺杂时,它们对应于本地等离子体振荡周围的杂质原子。这些效应有可能用于各种现代技术,从传感器到太阳能电池。大多数纳米等离子体效应的研究都集中在碱金属和贵金属系统与扩展的s-电子状态,而据信,掺杂TM原子与其更本地化的电荷作为一项规则,导致衰减的等离子体模式。我们表明,TM原子可以发挥建设性的作用,在等离子体激元产生的小链系统,等离子体激元模式,甚至可以出现在一些纯TM纳米链。

英文摘要:

We study the plasmonic properties of coupled noble-metal nanochains in the case of different number of coupled chains and doping by different transition-metal (TM) atoms within the time-dependent density-functional theory (TDDFT) approach. We find that as the number of chains in the array increases the plasmon peak shifts from the sub-eV towards the visible range. As doping with TM atoms increases, the visible absorption band broadens, owing to formation of additional plasmon peaks. The optical response is very sensitive to the type of doped atoms, their number and position; in particular, the additional peaks are most pronounced in the case of weak doping when they correspond to local plasmon oscillations around the impurity atom. These effects have a potential to be used in various modern technologies, from sensors to solar cells. Most of the studies of nano-plasmon effects have been focused on alkali- and noble-metal systems with extended s-electron states, while it was believed that doping with TM atoms with their more localized charge as a rule leads to an attenuation of the plasmon modes. We demonstrate that TM atoms can play a constructive role in plasmon generation in small chain systems, and that plasmonic modes can emerge even in some pure TM nanochains.

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