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Experimental Check of Different Additional Boundary Conditions in Case of Spatial Dispersion
Author(s) -
Skettrup T.
Publication year - 1982
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.2221090225
Subject(s) - exciton , reflection (computer programming) , spectral line , surface (topology) , dispersion (optics) , free surface , condensed matter physics , crystal (programming language) , spatial dispersion , boundary (topology) , function (biology) , wave function , transmission (telecommunications) , optics , molecular physics , boundary value problem , surface wave , physics , materials science , atomic physics , quantum mechanics , geometry , mathematics , mathematical analysis , electrical engineering , engineering , evolutionary biology , computer science , biology , programming language
Reflection and transmission spectra are computed for the A‐ and B‐excitons in ZnO which exhibit spatial dispersion. The different additional boundary conditions are tested by comparison with the corresponding experimental spectra. Without exciton free surface layer the Pekar condition (perfect reflection and vanishing of excitonic wave function at the surface) yields the best fit to the experimental spectra. The agreement is improved if the damping is assumed k ‐dependent. With exciton free surface layer included it turns out that the best agreement is obtained if only part of the excitonic wave function is reflected from the surface. Without k ‐dependent damping about 50% must be reflected, and with k ‐dependent damping about 70% of the excitonic wave function must be reflected from the surface. A simple method is also described from which the transmission spectra of spatially dispersive crystal slabs with exciton free surface layers can be computed.