Influence of the Material Band Structure on Attosecond Electron Dynamics in Transition Metals

报告人摘要：

Attosecond (10^-18 s) science (attoscience) is a new frontier of science that allows us to investigate the fastest dynamics happening in atoms, molecules and materials. In this talk, I will give a general introduction about what we can learn from attoscience studies and how the dynamics on the attosecond timescales can be measured in experiments. High-order harmonic generation (HHG) so far have served as one of the most powerful tools for such studies. As an example of attoscience study, I will present our recent efforts in JILA to measure attosecond electron dynamics in transition metals by combining HHG light source with angle-resolved photoelectron spectroscopy (ARPES). In this work, we for the first time revealed the strong influence of material band structure on the attosecond electron dynamics in materials, enabled by good energy resolution and polarization, angle-dependent measurements. At the same time, we investigated the electron-electron interactions (screening and scattering) on this shortest timescale ever accessible in a material.