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Coulomb‐Renormalized Intraband Dynamics Probed by THz Emission
Author(s) -
Wolter F.,
Haring Bolivar P.,
Bartels G.,
Roskos H. G.,
Kurz H.,
Axt V. M.,
Köhler K.
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<31::aid-pssb31>3.0.co;2-x
Subject(s) - coulomb , physics , dephasing , excited state , condensed matter physics , exciton , terahertz radiation , biexciton , superlattice , coherence (philosophical gambling strategy) , dynamics (music) , atomic physics , quantum mechanics , electron , acoustics
THz emission from a narrow‐miniband superlattice excited at its lower band edge reveals a hyperbolic bias dependence of the emission frequency. This reflects the emission from Coulomb‐renormalized states, namely the anticrossing between the miniband exciton and the hh —2 and hh —1 Wannier‐Stark‐Ladder states visible in the interband absorption spectra. An analysis of the intraband and interband dephasing times, respectively, reveals that the intraband dynamics remains to be Coulomb‐renormalized even after the dephasing of the interband coherence. This demonstrates that THz emission is dominated by long‐lived excitionic contributions, in contrast to predictions at a Hartree‐Fock level. The dynamics controlled truncation (DCT) approach taking into account the dynamics of the four‐point correlation for the intraband current density is able to account for this experimental observation.