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\textit{Ab initio} calculation of many-body effects on the second-harmonic generation spectra of hexagonal SiC polytypes

Title\textit{Ab initio} calculation of many-body effects on the second-harmonic generation spectra of hexagonal SiC polytypes
Publication TypeJournal Article
Year of Publication2011
AuthorsHübener, H., Luppi E., & Veniard V.
Keywordsexcitons; many body; silicon compounds; TDDFT
Abstract

We investigate the influence of crystal local fields and excitonic effects on the spectrum of the second harmonic generation of three polytypes of silicon carbide by using time-dependent density-functional theory including many-body effects, namely, quasiparticle corrections through the scissors operator, crystal local field effects, and excitonic interaction. The relation between the scalar density response and the components of the rank 3 tensor d(2) is established by calculating the response along different polarization directions. We find that local-field effects, although necessary for a rigorous description in the theory, yield only small contributions to the spectra, whereas excitonic effects have a strong influence on the second harmonic generation. We compare static values of the second harmonic coefficients to recent measurements and obtain very good agreement.

JournalPhysical Review B
Volume83
Pagination115205
URLhttp://dx.doi.org/10.1103/PhysRevB.83.115205
Date Published2011/03
Citation Key1310