Nonradiative Plasmon Decay and Hot Carrier Dynamics: Effects of Phonons, Surfaces, and Geometry
Nonradiative Plasmon Decay and Hot Carrier Dynamics: Effects of Phonons, Surfaces, and Geometry
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DOI：
10.1021/acsnano.5b06199
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发表时间：
2016-01-01
期刊：
影响因子：
17.1
通讯作者：
Atwater, Harry A.
中科院分区：
文献类型：
--
作者：
Brown, Ana M.;Sundararaman, Ravishankar;Atwater, Harry A.
金属在从微波到紫外线的广泛频率范围内的行为在等离子激子、纳米光子学和超材料中引起了人们的兴趣。根据频率的不同，金属中集体激发的损失可能主要是经典的电阻效应或朗道衰减。在此背景下，我们提出了第一性原理计算，捕捉了表面等离子体衰变的所有重要微观机制，并预测了由此产生的初始激发载流子分布。具体地说，我们包括金属中声子辅助光学激发的从头计算预测，这对于弥合低频电阻损耗和高频直接带间跃迁之间的频率范围至关重要。在常用的等离子体材料金、银、铜和铝中，我们发现在带间阈值以下，阻性损耗与声子辅助载流子的产生竞争，但在阈值以上，直接跃迁产生的热载流子占主导地位。最后，我们预测了热载流子的能量依赖寿命和平均自由程，考虑了电子电子和电子-声子散射，从而为等离子体产生的载流子在纳米尺度上的输运提供了深入的了解。
The behavior of metals across a broad frequency range from microwave to ultraviolet frequencies is of interest in plasmonics, nanophotonics, and metamaterials. Depending on the frequency, losses of collective excitations in metals can be predominantly classical resistive effects or Landau damping. In this context, we present first principles calculations that capture all of the significant microscopic mechanisms underlying surface plasmon decay and predict the initial excited carrier distributions so generated. Specifically, we include ab initio predictions of phonon-assisted optical excitations in metals, which are critical to bridging the frequency range between resistive losses at low frequencies and direct interband transitions at high frequencies. In the commonly used plasmonic materials, gold, silver, copper, and aluminum, we find that resistive losses compete with phonon-assisted carrier generation below the interband threshold, but hot carrier generation via direct transitions dominates above threshold. Finally, we predict energy-dependent lifetimes and mean free paths of hot carriers, accounting for electron electron and electron-phonon scattering, to provide insight toward transport of plasmonically generated carriers at the nanoscale.