Bloch-phonon coupling and tunneling-induced coherent phonon excitation in semiconductor superlattices
نویسندگان
چکیده
The coupling of Bloch oscillations to longitudinal optical phonons is investigated in a narrow-well In0.53Ga0.47As/In0.52Al0.48As 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.
منابع مشابه
Well-width dependence of coupled Bloch-phonon oscillations in biased InGaAs/InAlAs superlattices
The coupling between Bloch oscillations and longitudinal optical (LO) phonons is investigated in ternary In0.53Ga0.47As / In0.52Al0.48As superlattices of different well widths. In femtosecond time-resolved studies, a strong increase of the coherent LO phonon amplitudes is observed when the Bloch oscillations are subsequently tuned into resonance with the different optical phonon modes of the te...
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