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Wave Vectors of Excitonic Polaritons in ZnCdSe/ZnSSe Superlattices Determined by Resonant Raman Scattering
Author(s) -
Semjonow A. Je.,
Pohl U. W.
Publication year - 1999
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/(sici)1521-3951(199909)215:1<275::aid-pssb275>3.0.co;2-c
Subject(s) - polariton , superlattice , raman scattering , phonon , dispersion relation , condensed matter physics , dispersion (optics) , scattering , physics , raman spectroscopy , exciton , optics
Resonant excitonic polariton scattering from ZnSe‐like LO phonons in ZnCdSe/ZnSSe superlattices is studied. Room temperature measurements show strong spatial dispersion effects leading to different Stokes and anti‐Stokes frequency shifts. To describe the experiments we determine wave vectors using a phonon dispersion relation which includes effects of confinement and a strain‐induced shift. Excitonic polariton wave vectors are derived from the phonon wave vectors by taking a positive and a negative branch of the polariton dispersion into account with exciton masses m * + = + 0.65 m 0 and m * — = —1.9 m 0 , respectively. Good agreement is obtained for Stokes processes and a reasonable agreement for anti‐Stokes scattering.