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Electronic structure and optical properties of BiSeI crystal
Author(s) -
Audzijonis A.,
Gaigalas G.,
Žigas L.,
Sereika R.,
Žaltauskas R.,
Balnionis D.,
Rėza A.
Publication year - 2009
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.200945110
Subject(s) - refractive index , attenuation coefficient , density functional theory , molar absorptivity , chemistry , anisotropy , crystal (programming language) , dielectric , ellipsometry , plane wave , spectral line , molecular physics , absorption spectroscopy , absorption (acoustics) , condensed matter physics , materials science , optics , computational chemistry , physics , thin film , quantum mechanics , optoelectronics , computer science , programming language , nanotechnology
Electronic structure and optical properties of BiSeI were investigated with ab initio calculations based on density‐functional theory (DFT). The full potential linearized augmented plane wave (FP‐LAPW) method was used with the generalized gradient approximation (GGA). The complex dielectric function and optical constants, such as optical absorption coefficient, refractive index, extinction coefficient, energy‐loss spectrum and reflectivity, were calculated. It is shown that the p‐states of Bi, Se and I play an important role in absorption and reflectivity constants. The calculated optical constants of BiSeI exhibit anisotropy in two directions ( x ‐ and c ‐axes). The experimental optical dielectric functions for single‐crystal BiSeI were determined using spectroscopic ellipsometry. The ellipsometry results were analyzed using the approximation of a pseudodielectric function (PDF). This method shows that experimental spectra consist of a four Lorentzian lines sum. The Lorentzian line parameters are obtained by minimization using the mean‐square method of the difference between the calculated and measured spectra of the dielectric constants. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)