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TT: Tiefe Temperaturen

TT 24: Postersitzung III: Korrelierte Elektronen, ”Orbital Physics”

TT 24.47: Poster

Wednesday, March 10, 2004, 14:30–19:00, Poster A

Orbital excitations in LaTiO₃ and YTiO₃ investigated by infrared and Raman spectroscopy — •A. Gössling¹, R. Rückamp¹, M. Grüninger¹, M. Cwik¹, H Roth¹, T. Lorenz¹, A. Freimuth¹, B. Keimer² und C. Ulrich² — ¹II. Physikalisches Institut, Universität zu Köln — ²Max-Planck-Institut FKF, Stuttgart

There is still discussion about the puzzling compound LaTiO₃ [1,2,3]. We compare LaTiO₃ with orbitally ordered YTiO₃ using IR and Raman spectroscopy. With IR we observe broad peaks at approximately 0.30 eV in both compounds, with Raman at 0.25 eV. The difference in energy is due to the simultaneous excitation of a phonon in IR spectroscopy, breaking the parity selection rule. This clearly reveals the even parity of the excitation, typical for orbital excitations. We discuss the origin of the peaks within the framework of different theoretical models. Supported by the DFG through SFB 608.

[1] B. Keimer et al., Phys. Rev. Lett. 85, 3946 (2000).

[2] G. Khaliullin et al., Phys. Rev. Lett. 85, 3950 (2000).

[3] M. Cwik et al., Phys. Rev. B 68, 060401 (2003).