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HL: Halbleiterphysik
HL 38: Poster III: Transporteigenschaften (1-14), Optische Eigenschaften (15-31), Grenz-/Oberfl
ächen (32-44), Heterostrukturen (45-57), Bauelemente (58-67), Gitterdynamik (68-69), Diamant (70), Raster-Tunnel-Mikroskopie (71)
HL 38.15: Poster
Thursday, March 30, 2000, 14:00–19:00, B
Macroscopic dielectric function of perovskites by the ELAPW-k→·p→ method — •R. Bahnsen, E.E. Krasovskii, O.V. Krasovska, and W. Schattke — Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität Kiel, Leibnizstr. 15, 24098 Kiel
Optical spectra of SrTiO3, BaTiO3, and LaTiO3 perovskite
oxides are analyzed on the basis of the ab initio macroscopic
dielectric function. The self-consistent energy band structure and the
dielectric matrix of the complex oxides are calculated with the extended linear
augmented plane wave k→·p→ method [1].
The nonmuffin-tin crystal potential is constructed using the augmented
Fourier components method [2]. To calculate the dielectic matrix the
all-electron wave functions are expressed in terms of plane waves using a
gouging technique described in
[2]. The origin of UV spectral structures is elucidated. The chemical
trends in the formation of the UV reflectivity are discussed. The inclusion
of local field corrections shifts spectral structures due to semi-core
Sr 4p, Ba 5p, La 5p, and Ti 3p excitations by several eV to higher
energies. Calculated reflectivity and optical conductivity curves
agree well with the experiment.
[1] E.E. Krasovskii, W. Schattke Phys.Rev. B 56 (1997) 12874.
[2] E.E. Krasovskii, F. Starrost, W. Schattke Phys.Rev. B 59 (1999) 10504.