Dielectric tensor of monoclinic Ga2O3 single crystals in the spectral range 0.5–8.5 eV

The dielectric tensor of Ga2O3 in the monoclinic (β) phase was determined by generalized spectroscopic ellipsometry in a wide spectral range from 0.5 eV to 8.5 eV as well as by density functional theory calculations combined with many-body perturbation theory including quasiparticle and excitonic ef...

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Bibliographic Details
Main Authors: C. Sturm, J. Furthmüller, F. Bechstedt, R. Schmidt-Grund, M. Grundmann
Format: Article
Language:English
Published: AIP Publishing LLC 2015-10-01
Series:APL Materials
Online Access:http://dx.doi.org/10.1063/1.4934705
Description
Summary:The dielectric tensor of Ga2O3 in the monoclinic (β) phase was determined by generalized spectroscopic ellipsometry in a wide spectral range from 0.5 eV to 8.5 eV as well as by density functional theory calculations combined with many-body perturbation theory including quasiparticle and excitonic effects. The dielectric tensors obtained by both methods are in excellent agreement with each other and the observed transitions in the dielectric function are assigned to the corresponding valence bands. It is shown that the off-diagonal element of the dielectric tensor reaches values up to |εxz| ≈ 0.30 and cannot be neglected. Even in the transparent spectral range where it is quite small (|εxz| < 0.02) it causes a rotation of the dielectric axes around the symmetry axis of up to 20°.
ISSN:2166-532X