Ultrafast dynamics and resonance effects in photoemission from surfaces

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05393
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Chiba University
• Principal Investigator: Krueger Peter 千葉大学, 大学院工学研究院, 教授 (30706362)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 光物性 / 表面 / 界面

Outline of Final Research Achievements

In this project we have made good progress in the understanding of the photoemission process for (1) time delay and (2) resonance effect upon core-level excitation. (1) By directly comparing the solution of the time-dependent Schroedinger equation with a multiple scattering calculation in a one-dimensional model, we have shown how Wigner delay theory can be generalized from atoms to solids. Second, we have explained the oscillations of the time delay as a function of energy, observed in photoemission from Cu, by ab initio calculations [Optica 4, 1492]. (2) We have developed a theory and computer code for angle-resolved photoemission/photoelectron diffraction at core-level resonances of 3d metals by combining atomic multiplet theory and multiple scattering [J.Phys.Soc.Jpn 87, 061007]. We have fully reproduced the experimental resonant photoemission spectra of Ni(111), and have explained the recent, first observation of the Daimon effect in resonant photoelectron diffraction.

Free Research Field

物性Ⅰ

Academic Significance and Societal Importance of the Research Achievements

超高速原子・電子現象の研究は、物質の基本的な動的過程を理解する上で非常に重要なテーマである。　本プロジェクトでは、そのような超高速過程の一つである1フェムト秒以下で起こる表面からの光電子放出遅延現象についての理論的考察に進展が見られた。さらに、共鳴光電子回折の正確な理論を初めて開発した。この手法により、低消費電力電子デバイスの実現が期待されるスピントロニクス材料の磁気的・電子的状態を調べることができる。