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Influence of LO‐Phonon Emission on Bloch Oscillations in Semiconductor Superlattices
Author(s) -
Wolter F.,
Roskos H. G.,
Haring Bolivar P.,
Bartels G.,
Kurz H.,
Köhler K.,
Grahn H. T.,
Hey R.
Publication year - 1997
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(199711)204:1<83::aid-pssb83>3.0.co;2-b
Subject(s) - phonon , physics , electron , bloch oscillations , condensed matter physics , coherence (philosophical gambling strategy) , relaxation (psychology) , superlattice , spectroscopy , atomic physics , excitation , femtosecond , terahertz radiation , quantum beats , population , semiconductor , picosecond , optoelectronics , optics , quantum mechanics , psychology , social psychology , laser , demography , sociology
The intraband phase coherence of electronic Bloch wavepackets in semiconductor superlattices is partially conserved when electrons undergo energy relaxation by LO‐phonon emission. The decay time of the intraband coherence as probed by terahertz‐emission spectroscopy is found to be unaffected by excitation below or above the threshold for LO‐phonon emission. On the other hand, the population relaxation probed by femtosecond optical transmission spectroscopy is drastically accelerated when the threshold is reached. Electrons which have undergone LO‐phonon emission form a more localized distribution in k ‐space giving rise to a stronger THz signal.