邀请人：周发然 副研究员（9677）

报告摘要：
The orbital angular momentum of electrons offers a promising, yet underexplored, degree of freedom for ultrafast, energy-efficient information processing. As the foundation of orbitronics, understanding how orbital polarizations propagate and convert into charge currents is essential but remains elusive due to the challenge in disentangling orbital and spin dynamics in thin films. While some theoretical studies predict that orbital transport is constrained to sub-atomic-layer scales in materials, recent experiments have reported exceptionally long orbital diffusion lengths. To address this contradiction, we combine terahertz emission spectroscopy with a wedge-sample platform to systematically investigate spin and orbital transport in heavy metals with sub-nanometer resolution. Our measurements access the previously unexplored thin-film regimes (<3 nm), uncovering anomalous behaviors that challenge the prevailing interpretations of long-range orbital transport. We consistently find the orbital diffusion lengths (λL) to be substantially shorter than the spin diffusion lengths (λS) in heavy metals, with λL in W approaching 0.36 nm. Interface-sensitive control experiments further rule out interfacial orbital-to-charge conversion as the dominant mechanism, supporting the bulk inverse orbital Hall effect as the primary conversion process.

报告人简介：
陶镇生，复旦大学物理学系研究员、博士生导师。本科和硕士毕业于复旦大学物理学系，博士毕业于美国密歇根州立大学物理天文系。多年来围绕超快光学、超快光物质相互作用方向开展了多项原创工作。至今在包括Science, Nature Nanotechnology, eLight, Light:Science&Applications，PRL等刊物发表论文50余篇。先后获得国家 “高层次海外青年人才”，德国“洪堡学者”，上海市“东方学者”特聘教授。