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Elementary relaxation processes investigated by femtosecond photoelectron spectroscopy of two‐dimensional materials
Author(s) -
Bovensiepen U.,
Kirchmann P.S.
Publication year - 2012
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.201000035
Subject(s) - femtosecond , atomic physics , excitation , photoemission spectroscopy , electron , excited state , relaxation (psychology) , physics , spectroscopy , x ray photoelectron spectroscopy , electron spectroscopy , ultrashort pulse , laser , materials science , optics , nuclear magnetic resonance , quantum mechanics , psychology , social psychology
Elementary scattering processes in solid matter occur on ultrafast timescales and photoelectron spectroscopy in the time domain represents an excellent tool for their analysis. Conventional photoemission accesses binding energies of electronic states and their momentum dispersion. The use of femtosecond laser pulses in pump‐probe experiments allows obtaining direct insights to the energy and momentum dependence of ultrafast dynamics. This article introduces the elementary interaction processes and emphasizes recent work performed in this rapidly developing field. Decay processes in the low excitation limit are addressed, where electrons decay according to their interaction with carriers in equilibrium. Here, hot electron relaxation in epitaxial metallic film is reviewed. In the limit of an intense optical excitation, scattering of the excited electrons among each other establishes a non‐equilibrium state. Results on charge‐density wave materials and the effect of coherent nuclear motion on the electronic structure, which can break low symmetry ground states, are discussed. Figure reprinted with permission from [71].