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Multiple LO‐phonon Raman scattering and hot excitons
Author(s) -
TralleroGiner C.,
Riera R.
Publication year - 1989
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/pssb.2221520139
Subject(s) - exciton , scattering , raman scattering , phonon , atomic physics , biexciton , physics , relaxation (psychology) , condensed matter physics , cross section (physics) , annihilation , electron , chemistry , raman spectroscopy , quantum mechanics , psychology , social psychology
A theory is developed which describes multiphonon resonance Raman scattering (MPRS) processes in polar semiconductors when the incident radiation frequency ω 1 is above the fundamental absorption region. A general formula for the MPRS cross‐section based on the exciton distribution function is presented as a function of ω 1 , the indirect creation and annihilation probabilities, the exciton lifetime, and the transition probabilities between different exciton states. The different role of hot‐exciton transitions and their main contribution to the cross‐section is investigated. It is shown that the cross‐sections depend greatly on the ratio of the electron and hole effective masses. Using that and earlier theoretical results for the exciton scattering, the scattering lines showing intensity alternation in InI and InBr are explained if the electron and hole effective masses are nearly equal. The final result corresponds to a cascade model of exciton relaxation where the main transitions are between 2p and 2s exciton states. An approximate expression for the MPRS cross‐section is given.