研究・研究者
研究会・セミナー
| 演 題 | ｢Transient excitons at metal surfaces｣ |
|---|---|
| 日 時 | 2014年02月18日(火) 16:00 |
| 講演者 | Hrvoje Petek 教授 (Department of Physics and Astronomy, University of Pittsburgh, USA) |
| 場 所 | 分子科学研究所 研究棟2階 201号室 |
| 概 要 | Excitons, electron-hole pairs bound by the Coulomb potential, are fundamental quasiparticles of coherent light-matter interaction energizing processes from photosynthesis to optoelectronics. Excitons are observed in semiconductors, and their existence is implicit in the quantum theory of metals, yet their appearance is tenuous due to the screening of the Coulomb interaction on sub-femtosecond timescale. Here we explore the fundamental polaritonic and excitonic responses of noble metal, copper and silver, surfaces. Using three-dimensional energy, momentum, and time-resolved multiphoton-photoemission spectroscopy we show that rather than the external excitation field, the internal fields representing coherent quasiparticle correlations associated with the interband and excitonic polarizations dominate surface multiphoton excitation processes. The multiphoton photoemission spectra of Cu(111) and Ag(111) surfaces reveal a new non-Einsteinian mode of photoemission with potential applications to ultrafast nonlinear optics of metals. |
| その他 | Hrvoje Petek 教授 http://www.physicsandastronomy.pitt.edu/people/hrvoje_petek |
| お問合せ先 | 古谷祐詞、山本浩史（2013年度分子研コロキウム委員） |
