AuPt超晶格中电子能量的超快耗散局域化
Ultrafast Dissipative Localization of Electronic Energy in AuPt Superlattices
- Universität Potsdam（波茨坦大学）
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy（马克斯·玻恩非线性光学和短脉冲光谱研究所）
- European X-ray Free-Electron Laser Facility（欧洲X射线自由电子激光设施）
- Helmholtz-Zentrum Berlin（赫尔姆霍兹柏林中心）
- MAX IV Laboratory, Lund University（隆德大学MAX IV实验室）
- University of Regensburg（雷根斯堡大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文通过超快X射线衍射实验证明，AuPt超晶格中电子能量在飞秒尺度内耗散局域化至Pt组分，源于Pt大电子热容与快速电子输运，实现纳米尺度能量分布的飞秒控制。
AI中文摘要：
控制吸收光能的空间分布是纳米级光热化学、等离激元和超快材料控制的核心问题。在此，我们证明金属AuPt超晶格在几百飞秒内将电子能量集中于Pt中，无论两种组分之间的初始能量分布如何。超快X射线衍射通过AuPt界面处应力不平衡驱动的相干570 GHz超晶格声子的振幅来追踪这种能量再分布。尽管在400 nm处吸收近乎均匀，观察到的晶格运动与主要由Pt吸收的800 nm激发产生的运动相同。这种耗散驱动的能量局域化源于Pt的大电子热容和通过超晶格的快速电子输运，为纳米级能量分布的飞秒控制提供了一条途径。
英文摘要：
Controlling the spatial distribution of absorbed optical energy is central to nanoscale photothermal chemistry, plasmonics, and ultrafast materials control. Here, we show that a metallic AuPt superlattice concentrates electronic energy in Pt within a few hundred femtoseconds, regardless of the initial energy distribution between the two constituents. Ultrafast X-ray diffraction follows this energy redistribution through the amplitude of a coherent 570 GHz superlattice phonon driven by the stress imbalance at the AuPt interfaces. Despite the nearly homogeneous absorption at 400 nm, the observed lattice motion is identical to that produced by 800 nm excitation, which is absorbed predominantly in Pt. This dissipation driven localization of energy arises from the large electronic heat capacity of Pt and rapid electronic transport through the superlattice, providing a route to femtosecond control of nanoscale energy distributions.
