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Correlations Destroy Acoustic Plasmons in Superlattices
Author(s) -
Golden K. I.,
Kalman G.
Publication year - 1993
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.2221800224
Subject(s) - superlattice , plasmon , random phase approximation , wavelength , condensed matter physics , perpendicular , materials science , raman spectroscopy , function (biology) , phase (matter) , quasiparticle , order (exchange) , wavenumber , mode (computer interface) , optics , physics , mathematics , quantum mechanics , geometry , superconductivity , finance , evolutionary biology , economics , biology , computer science , operating system
It is demonstrated that interlayer correlations bring about important qualitative changes in the collective mode structure of superlattices, as compared to the random‐phase‐approximation predictions. The RPA acoustic plasmon is converted into an optic‐like mode where the k = 0 long‐wavelength frequency is a sensitive function of the strength of the interlayer correlations and of q , the wave number along the direction perpendicular to the layers. The result should motivate Raman measurements on GaAs/AlGaAs samples in parameter domains where the d / a ratio ( d is the separation distance between adjacent layers, a the interparticle spacing within a layer) is of order unity and where r s > 2.