Bloch-phonon coupling and tunneling-induced coherent phonon excitation in semiconductor superlattices
Author(s) -
M. Först,
H. Kurz,
T. Dekorsy,
Richard P. Leavitt
Publication year - 2003
Publication title -
physical review. b, condensed matter
Language(s) - English
Resource type - Journals
eISSN - 1095-3795
pISSN - 0163-1829
DOI - 10.1103/physrevb.67.085305
Subject(s) - condensed matter physics , superlattice , phonon , physics , dephasing , bloch oscillations , quantum tunnelling , excitation , scattering , coupling (piping) , amplitude , raman scattering , resonance (particle physics) , raman spectroscopy , atomic physics , quantum mechanics , materials science , metallurgy
The coupling of Bloch oscillations to longitudinal optical phonons is investigated in a narrow-well In 0 . 5 3 Ga 0 . 4 7 As/In 0 . 5 2 Al 0 . 4 8 As superlattice. A strong increase of coherent phonon amplitudes is observed when the Bloch oscillations are subsequently tuned into resonance with different optical phonon modes. The rapid dephasing of the Bloch oscillations due to field induced tunneling from the weakly bound miniband into above-barrier continuum states leads to an additional and new excitation process of coherent phonons in superlattices at high electric fields. Polarization dependent measurements confirm their generation via Coulomb interaction excluding any contribution through impulsively stimulated Raman scattering.
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