界面扩散动力学的三维逐原子测量
Three-dimensional atom-by-atom measurement of interface diffusion dynamics
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中文总结 AI 辅助
本研究结合MEMS脉冲淬火加热与原子电子断层扫描，逐原子重建Pd@Pt核壳纳米颗粒的三维构型，校正同种原子位移偏差，测得Pd扩散激活能为1.10 eV，并揭示层与晶面依赖的输运路径，建立了三维逐原子扩散测量框架。
中文摘要 AI 辅助
界面处的扩散决定了材料和器件的形成、演化与功能。通常，这种扩散通过平滑的浓度分布和体相输运系数来测量，而这些量是对离散原子重排的平均化处理。然而，在仅有几个原子层宽的纳米尺度界面处，这种粗粒化处理掩盖了局部的三维（3D）原子输运，且标量扩散系数无法完全描述按物种、层和晶面分辨的再分布。关键的观测对象是原子本身的离散三维再分布，而非平均化的分布曲线。在此，我们将微机电系统（MEMS）脉冲淬火加热与原子电子断层扫描（AET）相结合，重建了同一相干Pd@Pt核壳纳米颗粒的五个三维原子构型，每个构型对应一个明确的热状态。物种守恒的一对一分配将相邻构型关联起来，而标记参考模拟则校正了由同种原子不可区分性引起的位移偏差。校正后的Pd扩散率遵循阿伦尼乌斯行为，表观激活能为1.10 eV，与受迁移限制的空位介导输运机制一致。原子层跃迁统计进一步表明，三维迁移率的增加可以与净化学转移的下降共存，并揭示了被标量扩散率隐藏的晶面依赖路径。综合这些测量，我们建立了一个三维逐原子框架，将身份校正后的迁移率与埋藏纳米界面处按物种、层和晶面分辨的输运联系起来。
英文摘要
Diffusion at interfaces governs how materials and devices form, evolve and function. It is usually measured through smooth concentration profiles and bulk transport coefficients, which average over the discrete atomic rearrangements. At nanoscale interfaces only a few atomic layers wide, however, such coarse-graining obscures the local three-dimensional (3D) atomic transport, and scalar diffusion coefficients cannot fully describe species-, layer- and facet-resolved redistribution. The essential observable is the discrete 3D redistribution of atoms themselves, beyond an averaged profile. Here we combine micro-electro-mechanical systems (MEMS) pulse-quench heating with atomic electron tomography (AET) to reconstruct five 3D atomic configurations of the same coherent Pd@Pt core-shell nanoparticle, each corresponding to a well-defined thermal state. Species-conserving one-to-one assignment links neighbouring configurations, and labelled reference simulations correct the displacement bias caused by indistinguishable same-species atoms. The corrected Pd diffusivities follow Arrhenius behaviour, giving an apparent activation energy of 1.10 eV, consistent with migration-limited vacancy-mediated transport. Atomic-layer transition statistics further show that increasing 3D mobility can coexist with declining net chemical transfer and reveal facet-dependent pathways hidden by the scalar diffusivity. Together, these measurements establish a 3D atom-by-atom framework that connects identity-corrected mobility to species-, layer- and facet-resolved transport at buried nanointerfaces.
发表机构
- Korea Advanced Institute of Science and Technology (KAIST)（韩国科学技术院）
- Korea Institute of Energy Research (KIER)（韩国能源研究院）
- University of Science and Technology (UST)（科学技术联合大学院大学）
- Chungnam National University（忠南国立大学）
机构由 AI 辅助整理，请以论文原文为准。
