Regensburg 2000 – wissenschaftliches Programm

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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

Donnerstag, 30. März 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.